diff --git a/backend/src/db/migrate.ts b/backend/src/db/migrate.ts
index 5c4c187..70c388d 100644
--- a/backend/src/db/migrate.ts
+++ b/backend/src/db/migrate.ts
@@ -5,7 +5,7 @@ import { uniqueSlug } from '../lib/slugify.js';
 
 const dbType = process.env.DB_TYPE || 'sqlite';
 console.log(`Database type: ${dbType}`);
-console.log(`Database URL: ${process.env.DATABASE_URL?.substring(0, 30)}...`);
+// Do not log DATABASE_URL: it may contain credentials.
 
 async function migrate() {
   console.log('Running migrations...');
@@ -43,6 +43,9 @@ async function migrate() {
     try {
       await (db as any).run(sql`ALTER TABLE users ADD COLUMN account_status TEXT NOT NULL DEFAULT 'active'`);
     } catch (e) { /* column may already exist */ }
+    try {
+      await (db as any).run(sql`ALTER TABLE users ADD COLUMN token_version INTEGER NOT NULL DEFAULT 0`);
+    } catch (e) { /* column may already exist */ }
 
     // Magic link tokens table
     await (db as any).run(sql`
@@ -541,6 +544,9 @@ async function migrate() {
     try {
       await (db as any).execute(sql`ALTER TABLE users ADD COLUMN account_status VARCHAR(20) NOT NULL DEFAULT 'active'`);
     } catch (e) { /* column may already exist */ }
+    try {
+      await (db as any).execute(sql`ALTER TABLE users ADD COLUMN token_version INTEGER NOT NULL DEFAULT 0`);
+    } catch (e) { /* column may already exist */ }
 
     // Magic link tokens table
     await (db as any).execute(sql`
@@ -974,6 +980,27 @@ async function migrate() {
     `);
   }
 
+  // Indexes on foreign-key / hot-filter columns (CREATE INDEX IF NOT EXISTS works on both engines)
+  const indexStatements = [
+    `CREATE INDEX IF NOT EXISTS tickets_event_id_idx ON tickets(event_id)`,
+    `CREATE INDEX IF NOT EXISTS tickets_user_id_idx ON tickets(user_id)`,
+    `CREATE INDEX IF NOT EXISTS tickets_booking_id_idx ON tickets(booking_id)`,
+    `CREATE INDEX IF NOT EXISTS tickets_status_idx ON tickets(status)`,
+    `CREATE INDEX IF NOT EXISTS payments_ticket_id_idx ON payments(ticket_id)`,
+    `CREATE INDEX IF NOT EXISTS payments_status_idx ON payments(status)`,
+    `CREATE INDEX IF NOT EXISTS email_logs_event_id_idx ON email_logs(event_id)`,
+    `CREATE INDEX IF NOT EXISTS magic_link_tokens_token_idx ON magic_link_tokens(token)`,
+  ];
+  for (const stmt of indexStatements) {
+    try {
+      if (dbType === 'sqlite') {
+        await (db as any).run(sql.raw(stmt));
+      } else {
+        await (db as any).execute(sql.raw(stmt));
+      }
+    } catch (e) { /* index may already exist */ }
+  }
+
   // Backfill slugs for any events that don't have one yet (shared across DB types).
   // Ordered by creation so duplicate titles get deterministic -2, -3 suffixes.
   const allEvents = await dbAll<{ id: string; title: string; slug: string | null }>(
diff --git a/backend/src/db/schema.ts b/backend/src/db/schema.ts
index c8e834a..1efc7ca 100644
--- a/backend/src/db/schema.ts
+++ b/backend/src/db/schema.ts
@@ -18,6 +18,8 @@ export const sqliteUsers = sqliteTable('users', {
   googleId: text('google_id'),
   rucNumber: text('ruc_number'),
   accountStatus: text('account_status', { enum: ['active', 'unclaimed', 'suspended'] }).notNull().default('active'),
+  // Incremented to invalidate previously issued JWTs (logout-everywhere, password change/reset)
+  tokenVersion: integer('token_version').notNull().default(0),
   createdAt: text('created_at').notNull(),
   updatedAt: text('updated_at').notNull(),
 });
@@ -359,6 +361,8 @@ export const pgUsers = pgTable('users', {
   googleId: varchar('google_id', { length: 255 }),
   rucNumber: varchar('ruc_number', { length: 15 }),
   accountStatus: varchar('account_status', { length: 20 }).notNull().default('active'),
+  // Incremented to invalidate previously issued JWTs (logout-everywhere, password change/reset)
+  tokenVersion: pgInteger('token_version').notNull().default(0),
   createdAt: timestamp('created_at').notNull(),
   updatedAt: timestamp('updated_at').notNull(),
 });
diff --git a/backend/src/index.ts b/backend/src/index.ts
index 495ef96..82d876d 100644
--- a/backend/src/index.ts
+++ b/backend/src/index.ts
@@ -56,6 +56,19 @@ app.use(
   })
 );
 
+// Baseline security headers on every response.
+const isProduction = process.env.NODE_ENV === 'production';
+app.use('*', async (c, next) => {
+  await next();
+  c.header('X-Content-Type-Options', 'nosniff');
+  c.header('X-Frame-Options', 'DENY');
+  c.header('Referrer-Policy', 'strict-origin-when-cross-origin');
+  c.header('X-XSS-Protection', '0');
+  if (isProduction) {
+    c.header('Strict-Transport-Security', 'max-age=31536000; includeSubDomains');
+  }
+});
+
 // OpenAPI specification
 const openApiSpec = {
   openapi: '3.0.0',
@@ -1827,15 +1840,34 @@ const openApiSpec = {
   },
 };
 
-// OpenAPI JSON endpoint
-app.get('/openapi.json', (c) => {
-  return c.json(openApiSpec);
+// API documentation is disabled in production to avoid exposing the full API
+// surface (and schema) to anonymous users. Enable locally / in non-prod only.
+if (!isProduction) {
+  // OpenAPI JSON endpoint
+  app.get('/openapi.json', (c) => {
+    return c.json(openApiSpec);
+  });
+
+  // Swagger UI
+  app.get('/api-docs', swaggerUI({ url: '/openapi.json' }));
+} else {
+  app.get('/openapi.json', (c) => c.json({ error: 'Not Found' }, 404));
+  app.get('/api-docs', (c) => c.json({ error: 'Not Found' }, 404));
+}
+
+// Static file serving for uploads.
+// Uploads are validated as images at write time, but as defense-in-depth we force
+// any non-image path to download as an opaque attachment so a stray/legacy
+// .html/.svg can never be rendered (and therefore never execute script) in-origin.
+app.use('/uploads/*', async (c, next) => {
+  await next();
+  const path = c.req.path.toLowerCase();
+  const isInlineImage = /\.(jpg|jpeg|png|gif|webp|avif)$/.test(path);
+  if (!isInlineImage) {
+    c.header('Content-Disposition', 'attachment');
+    c.header('Content-Type', 'application/octet-stream');
+  }
 });
-
-// Swagger UI
-app.get('/api-docs', swaggerUI({ url: '/openapi.json' }));
-
-// Static file serving for uploads
 app.use('/uploads/*', serveStatic({ root: './' }));
 
 // Health check
diff --git a/backend/src/lib/auth.ts b/backend/src/lib/auth.ts
index 26a42da..1c732a6 100644
--- a/backend/src/lib/auth.ts
+++ b/backend/src/lib/auth.ts
@@ -4,10 +4,21 @@ import bcrypt from 'bcryptjs';
 import crypto from 'crypto';
 import { Context } from 'hono';
 import { db, dbGet, dbAll, users, magicLinkTokens, userSessions } from '../db/index.js';
-import { eq, and, gt } from 'drizzle-orm';
+import { eq, and, gt, sql, isNull } from 'drizzle-orm';
 import { generateId, getNow, toDbDate } from './utils.js';
 
-const JWT_SECRET = new TextEncoder().encode(process.env.JWT_SECRET || 'your-super-secret-key-change-in-production');
+const DEFAULT_DEV_JWT_SECRET = 'your-super-secret-key-change-in-production';
+const rawJwtSecret = process.env.JWT_SECRET;
+
+// Never allow the insecure default in production: forgeable tokens = full account takeover.
+if (process.env.NODE_ENV === 'production' && (!rawJwtSecret || rawJwtSecret === DEFAULT_DEV_JWT_SECRET)) {
+  throw new Error('JWT_SECRET must be set to a strong, unique value in production. Refusing to start with the default secret.');
+}
+if (!rawJwtSecret) {
+  console.warn('[auth] JWT_SECRET is not set; using an insecure development default. Set JWT_SECRET in production.');
+}
+
+const JWT_SECRET = new TextEncoder().encode(rawJwtSecret || DEFAULT_DEV_JWT_SECRET);
 const JWT_ISSUER = 'spanglish';
 const JWT_AUDIENCE = 'spanglish-app';
 
@@ -15,6 +26,7 @@ export interface JWTPayload {
   sub: string;
   email: string;
   role: string;
+  tokenVersion?: number;
   iat: number;
   exp: number;
 }
@@ -84,23 +96,36 @@ export async function verifyMagicLinkToken(
       )
   );
 
+  // Use a single generic error for all invalid states to avoid leaking token state
+  const genericError = 'Invalid or expired token';
+
   if (!tokenRecord) {
-    return { valid: false, error: 'Invalid token' };
+    return { valid: false, error: genericError };
   }
 
   if (tokenRecord.usedAt) {
-    return { valid: false, error: 'Token already used' };
+    return { valid: false, error: genericError };
   }
 
   if (new Date(tokenRecord.expiresAt) < new Date()) {
-    return { valid: false, error: 'Token expired' };
+    return { valid: false, error: genericError };
   }
 
-  // Mark token as used
-  await (db as any)
+  // Atomically consume the token: only the request that flips used_at from NULL wins.
+  // This prevents a double-spend race where two concurrent requests both pass the
+  // read-time "not used" check above.
+  const result: any = await (db as any)
     .update(magicLinkTokens)
     .set({ usedAt: now })
-    .where(eq((magicLinkTokens as any).id, tokenRecord.id));
+    .where(and(
+      eq((magicLinkTokens as any).id, tokenRecord.id),
+      isNull((magicLinkTokens as any).usedAt)
+    ));
+
+  const affected = result?.changes ?? result?.rowCount ?? 0;
+  if (affected === 0) {
+    return { valid: false, error: genericError };
+  }
 
   return { valid: true, userId: tokenRecord.userId };
 }
@@ -175,18 +200,26 @@ export function validatePassword(password: string): { valid: boolean; error?: st
   return { valid: true };
 }
 
-export async function createToken(userId: string, email: string, role: string): Promise<string> {
-  const token = await new jose.SignJWT({ sub: userId, email, role })
+export async function createToken(userId: string, email: string, role: string, tokenVersion: number = 0): Promise<string> {
+  const token = await new jose.SignJWT({ sub: userId, email, role, tokenVersion })
     .setProtectedHeader({ alg: 'HS256' })
     .setIssuedAt()
     .setIssuer(JWT_ISSUER)
     .setAudience(JWT_AUDIENCE)
-    .setExpirationTime('7d')
+    .setExpirationTime('1d')
     .sign(JWT_SECRET);
   
   return token;
 }
 
+// Invalidate all previously issued JWTs for a user (logout-everywhere, password change/reset).
+export async function bumpTokenVersion(userId: string): Promise<void> {
+  await (db as any)
+    .update(users)
+    .set({ tokenVersion: sql`${(users as any).tokenVersion} + 1` })
+    .where(eq((users as any).id, userId));
+}
+
 export async function createRefreshToken(userId: string): Promise<string> {
   const token = await new jose.SignJWT({ sub: userId, type: 'refresh' })
     .setProtectedHeader({ alg: 'HS256' })
@@ -223,10 +256,44 @@ export async function getAuthUser(c: Context): Promise<any | null> {
     return null;
   }
   
+  // Never load the password hash into request context — it is only needed for
+  // explicit password-verification routes that query it separately.
   const user = await dbGet<any>(
-    (db as any).select().from(users).where(eq((users as any).id, payload.sub))
+    (db as any)
+      .select({
+        id: (users as any).id,
+        email: (users as any).email,
+        name: (users as any).name,
+        phone: (users as any).phone,
+        role: (users as any).role,
+        languagePreference: (users as any).languagePreference,
+        isClaimed: (users as any).isClaimed,
+        googleId: (users as any).googleId,
+        rucNumber: (users as any).rucNumber,
+        accountStatus: (users as any).accountStatus,
+        tokenVersion: (users as any).tokenVersion,
+        createdAt: (users as any).createdAt,
+        updatedAt: (users as any).updatedAt,
+      })
+      .from(users)
+      .where(eq((users as any).id, payload.sub))
   );
-  return user || null;
+
+  if (!user) {
+    return null;
+  }
+
+  // Reject tokens issued before a logout-everywhere / password change
+  if ((payload.tokenVersion ?? 0) !== (user.tokenVersion ?? 0)) {
+    return null;
+  }
+
+  // Suspended/unclaimed accounts must not retain API access via an old JWT
+  if (user.accountStatus && user.accountStatus !== 'active') {
+    return null;
+  }
+
+  return user;
 }
 
 export function requireAuth(roles?: string[]) {
@@ -252,3 +319,15 @@ export async function isFirstUser(): Promise<boolean> {
   );
   return !result || result.length === 0;
 }
+
+/** Fetch only the password hash column (never expose via getAuthUser). */
+export async function getUserPasswordHash(userId: string): Promise<string | null> {
+  const row = await dbGet<any>(
+    (db as any)
+      .select({ password: (users as any).password })
+      .from(users)
+      .where(eq((users as any).id, userId))
+  );
+  const hash = row?.password;
+  return hash && String(hash).length > 0 ? String(hash) : null;
+}
diff --git a/backend/src/lib/email.ts b/backend/src/lib/email.ts
index 5ff1449..efb9ecc 100644
--- a/backend/src/lib/email.ts
+++ b/backend/src/lib/email.ts
@@ -247,10 +247,20 @@ async function sendWithConsole(options: SendEmailOptions): Promise<SendEmailResu
 /**
  * Main send function that routes to the appropriate provider
  */
+// Mask an email address for logs: keep first char + domain (e.g. j***@example.com).
+function maskEmail(email: string): string {
+  const [local, domain] = String(email).split('@');
+  if (!domain) return '***';
+  const head = local.slice(0, 1);
+  return `${head}***@${domain}`;
+}
+
 async function sendEmail(options: SendEmailOptions): Promise<SendEmailResult> {
   const provider = getEmailProvider();
   
-  console.log(`[Email] Sending email via ${provider} to ${Array.isArray(options.to) ? options.to.join(', ') : options.to}`);
+  const recipientCount = Array.isArray(options.to) ? options.to.length : 1;
+  const sample = Array.isArray(options.to) ? options.to[0] : options.to;
+  console.log(`[Email] Sending email via ${provider} to ${maskEmail(sample)}${recipientCount > 1 ? ` (+${recipientCount - 1} more)` : ''}`);
   
   switch (provider) {
     case 'resend':
@@ -478,7 +488,7 @@ export const emailService = {
     
     // Replace variables
     const finalSubject = replaceTemplateVariables(subject, allVariables);
-    const finalBodyContent = replaceTemplateVariables(bodyHtml, allVariables);
+    const finalBodyContent = replaceTemplateVariables(bodyHtml, allVariables, true);
     const finalBodyHtml = wrapInBaseTemplate(finalBodyContent, { ...allVariables, subject: finalSubject });
     const finalBodyText = bodyText ? replaceTemplateVariables(bodyText, allVariables) : undefined;
     
@@ -1292,7 +1302,14 @@ export const emailService = {
     eventId?: string;
     sentBy?: string | null;
   }): Promise<{ success: boolean; logId?: string; error?: string }> {
-    const { to, toName, subject, bodyHtml, bodyText, replyTo, eventId, sentBy = null } = params;
+    const { to: rawTo, toName, subject: rawSubject, bodyHtml, bodyText, replyTo: rawReplyTo, eventId, sentBy = null } = params;
+
+    // Strip CR/LF from header-bound values to prevent email header injection
+    // (e.g. an attacker-supplied subject/replyTo smuggling extra headers/recipients).
+    const stripHeader = (v?: string) => (v ? v.replace(/[\r\n]+/g, ' ').trim() : v);
+    const to = stripHeader(rawTo) as string;
+    const subject = stripHeader(rawSubject) as string;
+    const replyTo = stripHeader(rawReplyTo);
     
     const allVariables = {
       ...this.getCommonVariables(),
diff --git a/backend/src/lib/emailTemplates.ts b/backend/src/lib/emailTemplates.ts
index 6340aba..876ffc5 100644
--- a/backend/src/lib/emailTemplates.ts
+++ b/backend/src/lib/emailTemplates.ts
@@ -1216,8 +1216,26 @@ Spanglish`,
   },
 ];
 
-// Helper function to replace template variables
-export function replaceTemplateVariables(template: string, variables: Record<string, any>): string {
+// Escape HTML-significant characters so substituted variable values can't inject markup.
+function escapeHtmlValue(value: string): string {
+  return value
+    .replace(/&/g, '&amp;')
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
+    .replace(/"/g, '&quot;')
+    .replace(/'/g, '&#x27;');
+}
+
+// Helper function to replace template variables.
+// When `escapeHtml` is true (HTML rendering contexts), substituted *values* are
+// HTML-escaped to prevent stored-XSS via attacker-influenced variables (e.g. event
+// location, attendee name). The template markup itself is never escaped. Subjects and
+// plain-text bodies pass `escapeHtml=false` so they don't show literal entities.
+export function replaceTemplateVariables(
+  template: string,
+  variables: Record<string, any>,
+  escapeHtml: boolean = false
+): string {
   let result = template;
   
   // Handle conditional blocks {{#if variable}}...{{/if}}
@@ -1229,16 +1247,20 @@ export function replaceTemplateVariables(template: string, variables: Record<str
   // Replace simple variables {{variable}}
   const variableRegex = /\{\{(\w+)\}\}/g;
   result = result.replace(variableRegex, (match, varName) => {
-    return variables[varName] !== undefined ? String(variables[varName]) : match;
+    if (variables[varName] === undefined) return match;
+    const raw = String(variables[varName]);
+    return escapeHtml ? escapeHtmlValue(raw) : raw;
   });
   
   return result;
 }
 
-// Helper to wrap content in the base template
+// Helper to wrap content in the base template.
+// `content` is treated as trusted HTML (it is the already-rendered body). The wrapper's
+// own variables (subject, year, etc.) are HTML-escaped on substitution.
 export function wrapInBaseTemplate(content: string, variables: Record<string, any>): string {
-  const wrappedContent = baseEmailWrapper.replace('{{content}}', content);
-  return replaceTemplateVariables(wrappedContent, variables);
+  const wrappedContent = baseEmailWrapper.replace('{{content}}', () => content);
+  return replaceTemplateVariables(wrappedContent, variables, true);
 }
 
 // Get all available variables for a template by slug
diff --git a/backend/src/lib/lnbits.ts b/backend/src/lib/lnbits.ts
index 5bdb13c..66cc131 100644
--- a/backend/src/lib/lnbits.ts
+++ b/backend/src/lib/lnbits.ts
@@ -80,11 +80,8 @@ export async function createInvoice(params: CreateInvoiceParams): Promise<LNbits
   }
 
   console.log('Creating LNbits invoice:', {
-    url: `${config.url}${apiEndpoint}`,
     amount: params.amount,
     unit: payload.unit,
-    memo: params.memo,
-    webhook: params.webhookUrl,
   });
 
   const response = await fetch(`${config.url}${apiEndpoint}`, {
diff --git a/backend/src/lib/rateLimit.ts b/backend/src/lib/rateLimit.ts
new file mode 100644
index 0000000..bcec78c
--- /dev/null
+++ b/backend/src/lib/rateLimit.ts
@@ -0,0 +1,75 @@
+import { Context } from 'hono';
+
+/**
+ * Simple in-memory rate limiter.
+ *
+ * Suitable for a single backend instance (the current deployment model). If the
+ * backend is ever scaled horizontally, replace the in-memory Map with a shared
+ * store (e.g. Redis) so limits are enforced across instances.
+ */
+
+interface Bucket {
+  count: number;
+  resetAt: number;
+}
+
+const buckets = new Map<string, Bucket>();
+
+// Periodically drop expired buckets so the Map does not grow unbounded.
+const cleanup = setInterval(() => {
+  const now = Date.now();
+  for (const [key, bucket] of buckets) {
+    if (now > bucket.resetAt) buckets.delete(key);
+  }
+}, 60_000);
+// Don't keep the process alive just for cleanup.
+(cleanup as any).unref?.();
+
+/** Best-effort client IP extraction (honours common reverse-proxy headers). */
+export function getClientIp(c: Context): string {
+  const forwarded = c.req.header('x-forwarded-for');
+  if (forwarded) return forwarded.split(',')[0].trim();
+  return c.req.header('x-real-ip') || 'unknown';
+}
+
+/**
+ * Consume one unit against a key. Returns whether the request is allowed and,
+ * when blocked, how many seconds until the window resets.
+ */
+export function consumeRateLimit(
+  key: string,
+  max: number,
+  windowMs: number
+): { allowed: boolean; retryAfter?: number } {
+  const now = Date.now();
+  const bucket = buckets.get(key);
+
+  if (!bucket || now > bucket.resetAt) {
+    buckets.set(key, { count: 1, resetAt: now + windowMs });
+    return { allowed: true };
+  }
+
+  bucket.count++;
+  if (bucket.count > max) {
+    return { allowed: false, retryAfter: Math.ceil((bucket.resetAt - now) / 1000) };
+  }
+  return { allowed: true };
+}
+
+/**
+ * Hono middleware factory that rate-limits by client IP.
+ * Use a distinct `prefix` per endpoint group so unrelated routes don't share a bucket.
+ */
+export function rateLimitMiddleware(opts: { max: number; windowMs: number; prefix: string }) {
+  return async (c: Context, next: () => Promise<void>) => {
+    const ip = getClientIp(c);
+    const result = consumeRateLimit(`${opts.prefix}:${ip}`, opts.max, opts.windowMs);
+    if (!result.allowed) {
+      return c.json(
+        { error: 'Too many requests. Please try again later.', retryAfter: result.retryAfter },
+        429
+      );
+    }
+    await next();
+  };
+}
diff --git a/backend/src/routes/admin.ts b/backend/src/routes/admin.ts
index 70feaeb..34cdab9 100644
--- a/backend/src/routes/admin.ts
+++ b/backend/src/routes/admin.ts
@@ -67,14 +67,14 @@ adminRouter.get('/dashboard', requireAuth(['admin', 'organizer']), async (c) =>
       .where(eq((payments as any).status, 'pending'))
   );
   
-  const paidPayments = await dbAll<any>(
+  const revenueRow = await dbGet<any>(
     (db as any)
-      .select()
+      .select({ total: sql<number>`COALESCE(SUM(${(payments as any).amount}), 0)` })
       .from(payments)
       .where(eq((payments as any).status, 'paid'))
   );
   
-  const totalRevenue = paidPayments.reduce((sum: number, p: any) => sum + Number(p.amount || 0), 0);
+  const totalRevenue = Number(revenueRow?.total || 0);
   
   const newContacts = await dbGet<any>(
     (db as any)
@@ -110,56 +110,52 @@ adminRouter.get('/dashboard', requireAuth(['admin', 'organizer']), async (c) =>
 
 // Get analytics data (admin)
 adminRouter.get('/analytics', requireAuth(['admin']), async (c) => {
-  // Get events with ticket counts
+  // Get events with ticket counts using grouped aggregates (avoids 3 queries per event).
   const allEvents = await dbAll<any>((db as any).select().from(events));
-  
-  const eventStats = await Promise.all(
-    allEvents.map(async (event: any) => {
-      const ticketCount = await dbGet<any>(
-        (db as any)
-          .select({ count: sql<number>`count(*)` })
-          .from(tickets)
-          .where(eq((tickets as any).eventId, event.id))
-      );
-      
-      const confirmedCount = await dbGet<any>(
-        (db as any)
-          .select({ count: sql<number>`count(*)` })
-          .from(tickets)
-          .where(
-            and(
-              eq((tickets as any).eventId, event.id),
-              eq((tickets as any).status, 'confirmed'),
-              ne((tickets as any).isGuest, 1)
-            )
-          )
-      );
-      
-      const checkedInCount = await dbGet<any>(
-        (db as any)
-          .select({ count: sql<number>`count(*)` })
-          .from(tickets)
-          .where(
-            and(
-              eq((tickets as any).eventId, event.id),
-              eq((tickets as any).status, 'checked_in'),
-              ne((tickets as any).isGuest, 1)
-            )
-          )
-      );
-      
-      return {
-        id: event.id,
-        title: event.title,
-        date: event.startDatetime,
-        capacity: event.capacity,
-        totalBookings: ticketCount?.count || 0,
-        confirmedBookings: confirmedCount?.count || 0,
-        checkedIn: checkedInCount?.count || 0,
-        revenue: (confirmedCount?.count || 0) * event.price,
-      };
-    })
+
+  const totalRows = await dbAll<any>(
+    (db as any)
+      .select({ eventId: (tickets as any).eventId, count: sql<number>`count(*)` })
+      .from(tickets)
+      .groupBy((tickets as any).eventId)
   );
+  const confirmedRows = await dbAll<any>(
+    (db as any)
+      .select({ eventId: (tickets as any).eventId, count: sql<number>`count(*)` })
+      .from(tickets)
+      .where(and(eq((tickets as any).status, 'confirmed'), ne((tickets as any).isGuest, 1)))
+      .groupBy((tickets as any).eventId)
+  );
+  const checkedInRows = await dbAll<any>(
+    (db as any)
+      .select({ eventId: (tickets as any).eventId, count: sql<number>`count(*)` })
+      .from(tickets)
+      .where(and(eq((tickets as any).status, 'checked_in'), ne((tickets as any).isGuest, 1)))
+      .groupBy((tickets as any).eventId)
+  );
+
+  const toMap = (rows: any[]) => {
+    const m = new Map<string, number>();
+    for (const r of rows) m.set(r.eventId, Number(r.count) || 0);
+    return m;
+  };
+  const totalMap = toMap(totalRows);
+  const confirmedMap = toMap(confirmedRows);
+  const checkedInMap = toMap(checkedInRows);
+
+  const eventStats = allEvents.map((event: any) => {
+    const confirmedBookings = confirmedMap.get(event.id) || 0;
+    return {
+      id: event.id,
+      title: event.title,
+      date: event.startDatetime,
+      capacity: event.capacity,
+      totalBookings: totalMap.get(event.id) || 0,
+      confirmedBookings,
+      checkedIn: checkedInMap.get(event.id) || 0,
+      revenue: confirmedBookings * event.price,
+    };
+  });
   
   return c.json({
     analytics: {
@@ -179,30 +175,25 @@ adminRouter.get('/export/tickets', requireAuth(['admin']), async (c) => {
   }
   
   const ticketList = await dbAll<any>(query);
+
+  const userIds = [...new Set(ticketList.map((t: any) => t.userId).filter(Boolean))];
+  const eventIds = [...new Set(ticketList.map((t: any) => t.eventId).filter(Boolean))];
+  const ticketIds = ticketList.map((t: any) => t.id);
+
+  const [userRows, eventRows, paymentRows] = await Promise.all([
+    userIds.length ? dbAll<any>((db as any).select().from(users).where(inArray((users as any).id, userIds))) : Promise.resolve([]),
+    eventIds.length ? dbAll<any>((db as any).select().from(events).where(inArray((events as any).id, eventIds))) : Promise.resolve([]),
+    ticketIds.length ? dbAll<any>((db as any).select().from(payments).where(inArray((payments as any).ticketId, ticketIds))) : Promise.resolve([]),
+  ]);
+
+  const usersById = new Map(userRows.map((u: any) => [u.id, u]));
+  const eventsById = new Map(eventRows.map((e: any) => [e.id, e]));
+  const paymentsByTicketId = new Map(paymentRows.map((p: any) => [p.ticketId, p]));
   
-  // Get user and event details for each ticket
-  const enrichedTickets = await Promise.all(
-    ticketList.map(async (ticket: any) => {
-      const user = await dbGet<any>(
-        (db as any)
-          .select()
-          .from(users)
-          .where(eq((users as any).id, ticket.userId))
-      );
-      
-      const event = await dbGet<any>(
-        (db as any)
-          .select()
-          .from(events)
-          .where(eq((events as any).id, ticket.eventId))
-      );
-      
-      const payment = await dbGet<any>(
-        (db as any)
-          .select()
-          .from(payments)
-          .where(eq((payments as any).ticketId, ticket.id))
-      );
+  const enrichedTickets = ticketList.map((ticket: any) => {
+      const user = usersById.get(ticket.userId);
+      const event = eventsById.get(ticket.eventId);
+      const payment = paymentsByTicketId.get(ticket.id);
       
       return {
         ticketId: ticket.id,
@@ -218,8 +209,7 @@ adminRouter.get('/export/tickets', requireAuth(['admin']), async (c) => {
         paymentAmount: payment?.amount,
         createdAt: ticket.createdAt,
       };
-    })
-  );
+    });
   
   return c.json({ tickets: enrichedTickets });
 });
diff --git a/backend/src/routes/auth.ts b/backend/src/routes/auth.ts
index ad34c63..74e1a47 100644
--- a/backend/src/routes/auth.ts
+++ b/backend/src/routes/auth.ts
@@ -14,10 +14,17 @@ import {
   createMagicLinkToken,
   verifyMagicLinkToken,
   invalidateAllUserSessions,
+  bumpTokenVersion,
   requireAuth,
+  getUserPasswordHash,
 } from '../lib/auth.js';
 import { generateId, getNow, toDbBool } from '../lib/utils.js';
 import { sendEmail } from '../lib/email.js';
+import { rateLimitMiddleware } from '../lib/rateLimit.js';
+
+// Per-IP rate limit for sensitive auth endpoints (registration, login, and all
+// email-dispatching flows) to curb credential stuffing and email flooding.
+const authRateLimit = rateLimitMiddleware({ max: 20, windowMs: 15 * 60 * 1000, prefix: 'auth' });
 
 // User type that includes all fields (some added in schema updates)
 type AuthUser = User & {
@@ -97,8 +104,7 @@ const passwordResetSchema = z.object({
 
 const claimAccountSchema = z.object({
   token: z.string(),
-  password: z.string().min(10, 'Password must be at least 10 characters').optional(),
-  googleId: z.string().optional(),
+  password: z.string().min(10, 'Password must be at least 10 characters'),
 });
 
 const changePasswordSchema = z.object({
@@ -111,7 +117,7 @@ const googleAuthSchema = z.object({
 });
 
 // Register
-auth.post('/register', zValidator('json', registerSchema), async (c) => {
+auth.post('/register', authRateLimit, zValidator('json', registerSchema), async (c) => {
   const data = c.req.valid('json');
   
   // Validate password strength
@@ -161,7 +167,7 @@ auth.post('/register', zValidator('json', registerSchema), async (c) => {
   
   await (db as any).insert(users).values(newUser);
   
-  const token = await createToken(id, data.email, newUser.role);
+  const token = await createToken(id, data.email, newUser.role, 0);
   const refreshToken = await createRefreshToken(id);
   
   return c.json({
@@ -179,7 +185,7 @@ auth.post('/register', zValidator('json', registerSchema), async (c) => {
 });
 
 // Login with email/password
-auth.post('/login', zValidator('json', loginSchema), async (c) => {
+auth.post('/login', authRateLimit, zValidator('json', loginSchema), async (c) => {
   const data = c.req.valid('json');
   
   // Check rate limit
@@ -224,7 +230,7 @@ auth.post('/login', zValidator('json', loginSchema), async (c) => {
   // Clear failed attempts on successful login
   clearFailedAttempts(data.email);
   
-  const token = await createToken(user.id, user.email, user.role);
+  const token = await createToken(user.id, user.email, user.role, user.tokenVersion ?? 0);
   const refreshToken = await createRefreshToken(user.id);
   
   return c.json({
@@ -244,7 +250,7 @@ auth.post('/login', zValidator('json', loginSchema), async (c) => {
 });
 
 // Request magic link login
-auth.post('/magic-link/request', zValidator('json', magicLinkRequestSchema), async (c) => {
+auth.post('/magic-link/request', authRateLimit, zValidator('json', magicLinkRequestSchema), async (c) => {
   const { email } = c.req.valid('json');
   
   const user = await dbGet<any>(
@@ -285,7 +291,7 @@ auth.post('/magic-link/request', zValidator('json', magicLinkRequestSchema), asy
 });
 
 // Verify magic link and login
-auth.post('/magic-link/verify', zValidator('json', magicLinkVerifySchema), async (c) => {
+auth.post('/magic-link/verify', authRateLimit, zValidator('json', magicLinkVerifySchema), async (c) => {
   const { token } = c.req.valid('json');
   
   const verification = await verifyMagicLinkToken(token, 'login');
@@ -302,7 +308,7 @@ auth.post('/magic-link/verify', zValidator('json', magicLinkVerifySchema), async
     return c.json({ error: 'Invalid token' }, 400);
   }
   
-  const authToken = await createToken(user.id, user.email, user.role);
+  const authToken = await createToken(user.id, user.email, user.role, user.tokenVersion ?? 0);
   const refreshToken = await createRefreshToken(user.id);
   
   return c.json({
@@ -322,7 +328,7 @@ auth.post('/magic-link/verify', zValidator('json', magicLinkVerifySchema), async
 });
 
 // Request password reset
-auth.post('/password-reset/request', zValidator('json', passwordResetRequestSchema), async (c) => {
+auth.post('/password-reset/request', authRateLimit, zValidator('json', passwordResetRequestSchema), async (c) => {
   const { email } = c.req.valid('json');
   
   const user = await dbGet<any>(
@@ -363,7 +369,7 @@ auth.post('/password-reset/request', zValidator('json', passwordResetRequestSche
 });
 
 // Reset password
-auth.post('/password-reset/confirm', zValidator('json', passwordResetSchema), async (c) => {
+auth.post('/password-reset/confirm', authRateLimit, zValidator('json', passwordResetSchema), async (c) => {
   const { token, password } = c.req.valid('json');
   
   // Validate password strength
@@ -389,14 +395,15 @@ auth.post('/password-reset/confirm', zValidator('json', passwordResetSchema), as
     })
     .where(eq((users as any).id, verification.userId));
   
-  // Invalidate all existing sessions for security
+  // Invalidate all existing sessions/JWTs for security
   await invalidateAllUserSessions(verification.userId!);
+  await bumpTokenVersion(verification.userId!);
   
   return c.json({ message: 'Password reset successfully. Please log in with your new password.' });
 });
 
 // Claim unclaimed account
-auth.post('/claim-account/request', zValidator('json', magicLinkRequestSchema), async (c) => {
+auth.post('/claim-account/request', authRateLimit, zValidator('json', magicLinkRequestSchema), async (c) => {
   const { email } = c.req.valid('json');
   
   const user = await dbGet<any>(
@@ -411,8 +418,8 @@ auth.post('/claim-account/request', zValidator('json', magicLinkRequestSchema),
     return c.json({ error: 'Account is already claimed' }, 400);
   }
   
-  // Create claim token (expires in 24 hours)
-  const token = await createMagicLinkToken(user.id, 'claim_account', 24 * 60);
+  // Create claim token (expires in 1 hour)
+  const token = await createMagicLinkToken(user.id, 'claim_account', 60);
   const claimLink = `${process.env.FRONTEND_URL || 'http://localhost:3000'}/auth/claim-account?token=${token}`;
   
   // Send email
@@ -425,7 +432,7 @@ auth.post('/claim-account/request', zValidator('json', magicLinkRequestSchema),
         <p>An account was created for you during booking. Click below to set up your login credentials.</p>
         <p><a href="${claimLink}" style="background-color: #3B82F6; color: white; padding: 12px 24px; text-decoration: none; border-radius: 6px; display: inline-block;">Claim Account</a></p>
         <p>Or copy this link: ${claimLink}</p>
-        <p>This link expires in 24 hours.</p>
+        <p>This link expires in 1 hour.</p>
       `,
     });
   } catch (error) {
@@ -436,12 +443,8 @@ auth.post('/claim-account/request', zValidator('json', magicLinkRequestSchema),
 });
 
 // Complete account claim
-auth.post('/claim-account/confirm', zValidator('json', claimAccountSchema), async (c) => {
-  const { token, password, googleId } = c.req.valid('json');
-  
-  if (!password && !googleId) {
-    return c.json({ error: 'Please provide either a password or link a Google account' }, 400);
-  }
+auth.post('/claim-account/confirm', authRateLimit, zValidator('json', claimAccountSchema), async (c) => {
+  const { token, password } = c.req.valid('json');
   
   const verification = await verifyMagicLinkToken(token, 'claim_account');
   
@@ -449,25 +452,21 @@ auth.post('/claim-account/confirm', zValidator('json', claimAccountSchema), asyn
     return c.json({ error: verification.error }, 400);
   }
   
+  const passwordValidation = validatePassword(password);
+  if (!passwordValidation.valid) {
+    return c.json({ error: passwordValidation.error }, 400);
+  }
+
   const now = getNow();
+  // Only set a password here. Linking a Google account requires a verified Google
+  // ID token via /google; we never trust a client-supplied googleId.
   const updates: Record<string, any> = {
     isClaimed: toDbBool(true),
     accountStatus: 'active',
+    password: await hashPassword(password),
     updatedAt: now,
   };
   
-  if (password) {
-    const passwordValidation = validatePassword(password);
-    if (!passwordValidation.valid) {
-      return c.json({ error: passwordValidation.error }, 400);
-    }
-    updates.password = await hashPassword(password);
-  }
-  
-  if (googleId) {
-    updates.googleId = googleId;
-  }
-  
   await (db as any)
     .update(users)
     .set(updates)
@@ -477,7 +476,7 @@ auth.post('/claim-account/confirm', zValidator('json', claimAccountSchema), asyn
     (db as any).select().from(users).where(eq((users as any).id, verification.userId))
   );
   
-  const authToken = await createToken(user.id, user.email, user.role);
+  const authToken = await createToken(user.id, user.email, user.role, user.tokenVersion ?? 0);
   const refreshToken = await createRefreshToken(user.id);
   
   return c.json({
@@ -498,13 +497,14 @@ auth.post('/claim-account/confirm', zValidator('json', claimAccountSchema), asyn
 });
 
 // Google OAuth login/register
-auth.post('/google', zValidator('json', googleAuthSchema), async (c) => {
+auth.post('/google', authRateLimit, zValidator('json', googleAuthSchema), async (c) => {
   const { credential } = c.req.valid('json');
   
   try {
-    // Verify Google token
-    // In production, use Google's library to verify: https://developers.google.com/identity/gsi/web/guides/verify-google-id-token
-    const response = await fetch(`https://oauth2.googleapis.com/tokeninfo?id_token=${credential}`);
+    // Verify the Google ID token. Google's tokeninfo endpoint validates the
+    // signature and expiry server-side; we additionally enforce the audience so a
+    // token minted for a different OAuth client cannot be replayed against us.
+    const response = await fetch(`https://oauth2.googleapis.com/tokeninfo?id_token=${encodeURIComponent(credential)}`);
     
     if (!response.ok) {
       return c.json({ error: 'Invalid Google token' }, 400);
@@ -515,11 +515,29 @@ auth.post('/google', zValidator('json', googleAuthSchema), async (c) => {
       email: string;
       name: string;
       email_verified: string;
+      aud?: string;
+      exp?: string;
     };
-    
-    if (googleData.email_verified !== 'true') {
+
+    // email_verified can be returned as boolean true or string "true"
+    if (String(googleData.email_verified) !== 'true') {
       return c.json({ error: 'Google email not verified' }, 400);
     }
+
+    // Enforce audience when a client ID is configured (closes token-confusion attacks)
+    const expectedAud = process.env.GOOGLE_CLIENT_ID;
+    if (expectedAud) {
+      if (googleData.aud !== expectedAud) {
+        return c.json({ error: 'Invalid Google token audience' }, 400);
+      }
+    } else {
+      console.warn('[auth] GOOGLE_CLIENT_ID is not set; skipping audience verification for Google login.');
+    }
+
+    // Reject expired tokens (defense-in-depth; tokeninfo also rejects them)
+    if (googleData.exp && Number(googleData.exp) * 1000 < Date.now()) {
+      return c.json({ error: 'Google token expired' }, 400);
+    }
     
     const { sub: googleId, email, name } = googleData;
     
@@ -584,7 +602,7 @@ auth.post('/google', zValidator('json', googleAuthSchema), async (c) => {
       user = newUser;
     }
     
-    const authToken = await createToken(user.id, user.email, user.role);
+    const authToken = await createToken(user.id, user.email, user.role, user.tokenVersion ?? 0);
     const refreshToken = await createRefreshToken(user.id);
     
     return c.json({
@@ -643,8 +661,9 @@ auth.post('/change-password', requireAuth(), zValidator('json', changePasswordSc
   }
   
   // Verify current password if user has one
-  if (user.password) {
-    const validPassword = await verifyPassword(currentPassword, user.password);
+  const existingHash = await getUserPasswordHash(user.id);
+  if (existingHash) {
+    const validPassword = await verifyPassword(currentPassword, existingHash);
     if (!validPassword) {
       return c.json({ error: 'Current password is incorrect' }, 400);
     }
@@ -660,12 +679,25 @@ auth.post('/change-password', requireAuth(), zValidator('json', changePasswordSc
       updatedAt: now,
     })
     .where(eq((users as any).id, user.id));
+
+  // Invalidate all previously issued JWTs so a stolen old token can't outlive the change,
+  // then hand the current client a fresh token so it stays logged in on this device.
+  await bumpTokenVersion(user.id);
+  const refreshedUser = await dbGet<any>(
+    (db as any).select().from(users).where(eq((users as any).id, user.id))
+  );
+  const newToken = await createToken(user.id, user.email, user.role, refreshedUser?.tokenVersion ?? 0);
   
-  return c.json({ message: 'Password changed successfully' });
+  return c.json({ message: 'Password changed successfully', token: newToken });
 });
 
-// Logout (client-side token removal, but we can log the action)
+// Logout - invalidate all previously issued JWTs for this user (logout everywhere)
 auth.post('/logout', async (c) => {
+  const user = await getAuthUser(c);
+  if (user) {
+    await invalidateAllUserSessions(user.id);
+    await bumpTokenVersion(user.id);
+  }
   return c.json({ message: 'Logged out successfully' });
 });
 
diff --git a/backend/src/routes/contacts.ts b/backend/src/routes/contacts.ts
index a86093c..9e26143 100644
--- a/backend/src/routes/contacts.ts
+++ b/backend/src/routes/contacts.ts
@@ -6,9 +6,14 @@ import { eq, desc } from 'drizzle-orm';
 import { requireAuth } from '../lib/auth.js';
 import { generateId, getNow } from '../lib/utils.js';
 import { emailService } from '../lib/email.js';
+import { rateLimitMiddleware } from '../lib/rateLimit.js';
 
 const contactsRouter = new Hono();
 
+// Per-IP rate limit for public, unauthenticated write endpoints (contact form,
+// newsletter subscribe/unsubscribe) to prevent spam and email flooding.
+const publicFormLimit = rateLimitMiddleware({ max: 5, windowMs: 10 * 60 * 1000, prefix: 'contacts' });
+
 // ==================== Sanitization Helpers ====================
 
 /**
@@ -33,14 +38,14 @@ function sanitizeHeaderValue(str: string): string {
 }
 
 const createContactSchema = z.object({
-  name: z.string().min(2),
-  email: z.string().email(),
-  message: z.string().min(10),
+  name: z.string().min(2).max(200),
+  email: z.string().email().max(254),
+  message: z.string().min(10).max(5000),
 });
 
 const subscribeSchema = z.object({
-  email: z.string().email(),
-  name: z.string().optional(),
+  email: z.string().email().max(254),
+  name: z.string().max(200).optional(),
 });
 
 const updateContactSchema = z.object({
@@ -48,7 +53,7 @@ const updateContactSchema = z.object({
 });
 
 // Submit contact form (public)
-contactsRouter.post('/', zValidator('json', createContactSchema), async (c) => {
+contactsRouter.post('/', publicFormLimit, zValidator('json', createContactSchema), async (c) => {
   const data = c.req.valid('json');
   const now = getNow();
   const id = generateId();
@@ -125,7 +130,7 @@ contactsRouter.post('/', zValidator('json', createContactSchema), async (c) => {
 });
 
 // Subscribe to newsletter (public)
-contactsRouter.post('/subscribe', zValidator('json', subscribeSchema), async (c) => {
+contactsRouter.post('/subscribe', publicFormLimit, zValidator('json', subscribeSchema), async (c) => {
   const data = c.req.valid('json');
   
   // Check if already subscribed
@@ -166,28 +171,30 @@ contactsRouter.post('/subscribe', zValidator('json', subscribeSchema), async (c)
 });
 
 // Unsubscribe from newsletter (public)
-contactsRouter.post('/unsubscribe', zValidator('json', z.object({ email: z.string().email() })), async (c) => {
+contactsRouter.post('/unsubscribe', publicFormLimit, zValidator('json', z.object({ email: z.string().email().max(254) })), async (c) => {
   const { email } = c.req.valid('json');
   
   const existing = await dbGet<any>(
     (db as any).select().from(emailSubscribers).where(eq((emailSubscribers as any).email, email))
   );
   
-  if (!existing) {
-    return c.json({ error: 'Email not found' }, 404);
+  // Always return the same response whether or not the address exists, to avoid
+  // leaking which emails are subscribed (enumeration).
+  if (existing && existing.status !== 'unsubscribed') {
+    await (db as any)
+      .update(emailSubscribers)
+      .set({ status: 'unsubscribed' })
+      .where(eq((emailSubscribers as any).id, existing.id));
   }
   
-  await (db as any)
-    .update(emailSubscribers)
-    .set({ status: 'unsubscribed' })
-    .where(eq((emailSubscribers as any).id, existing.id));
-  
-  return c.json({ message: 'Successfully unsubscribed' });
+  return c.json({ message: 'If this email was subscribed, it has been unsubscribed.' });
 });
 
 // Get all contacts (admin)
 contactsRouter.get('/', requireAuth(['admin', 'organizer']), async (c) => {
   const status = c.req.query('status');
+  const limit = Math.min(Math.max(parseInt(c.req.query('limit') || '100', 10) || 100, 1), 500);
+  const offset = Math.max(parseInt(c.req.query('offset') || '0', 10) || 0, 0);
   
   let query = (db as any).select().from(contacts);
   
@@ -195,7 +202,9 @@ contactsRouter.get('/', requireAuth(['admin', 'organizer']), async (c) => {
     query = query.where(eq((contacts as any).status, status));
   }
   
-  const result = await dbAll(query.orderBy(desc((contacts as any).createdAt)));
+  const result = await dbAll(
+    query.orderBy(desc((contacts as any).createdAt)).limit(limit).offset(offset)
+  );
   
   return c.json({ contacts: result });
 });
@@ -255,6 +264,8 @@ contactsRouter.delete('/:id', requireAuth(['admin']), async (c) => {
 // Get all subscribers (admin)
 contactsRouter.get('/subscribers/list', requireAuth(['admin', 'marketing']), async (c) => {
   const status = c.req.query('status');
+  const limit = Math.min(Math.max(parseInt(c.req.query('limit') || '100', 10) || 100, 1), 1000);
+  const offset = Math.max(parseInt(c.req.query('offset') || '0', 10) || 0, 0);
   
   let query = (db as any).select().from(emailSubscribers);
   
@@ -262,7 +273,9 @@ contactsRouter.get('/subscribers/list', requireAuth(['admin', 'marketing']), asy
     query = query.where(eq((emailSubscribers as any).status, status));
   }
   
-  const result = await dbAll(query.orderBy(desc((emailSubscribers as any).createdAt)));
+  const result = await dbAll(
+    query.orderBy(desc((emailSubscribers as any).createdAt)).limit(limit).offset(offset)
+  );
   
   return c.json({ subscribers: result });
 });
diff --git a/backend/src/routes/dashboard.ts b/backend/src/routes/dashboard.ts
index 9895c5c..4e2ec47 100644
--- a/backend/src/routes/dashboard.ts
+++ b/backend/src/routes/dashboard.ts
@@ -2,8 +2,8 @@ import { Hono } from 'hono';
 import { zValidator } from '@hono/zod-validator';
 import { z } from 'zod';
 import { db, dbGet, dbAll, users, tickets, payments, events, invoices, User } from '../db/index.js';
-import { eq, desc, and, gt, sql } from 'drizzle-orm';
-import { requireAuth, getUserSessions, invalidateSession, invalidateAllUserSessions, hashPassword, validatePassword } from '../lib/auth.js';
+import { eq, desc, and, gt, sql, inArray } from 'drizzle-orm';
+import { requireAuth, getUserSessions, invalidateSession, invalidateAllUserSessions, bumpTokenVersion, createToken, hashPassword, validatePassword, getUserPasswordHash } from '../lib/auth.js';
 import { generateId, getNow } from '../lib/utils.js';
 
 // User type that includes all fields (some added in schema updates)
@@ -37,6 +37,8 @@ dashboard.get('/profile', async (c) => {
   const now = new Date();
   const membershipDays = Math.floor((now.getTime() - createdDate.getTime()) / (1000 * 60 * 60 * 24));
   
+  const hasPassword = !!(await getUserPasswordHash(user.id));
+
   return c.json({
     profile: {
       id: user.id,
@@ -47,7 +49,7 @@ dashboard.get('/profile', async (c) => {
       rucNumber: user.rucNumber,
       isClaimed: user.isClaimed,
       accountStatus: user.accountStatus,
-      hasPassword: !!user.password,
+      hasPassword,
       hasGoogleLinked: !!user.googleId,
       memberSince: user.createdAt,
       membershipDays,
@@ -103,34 +105,31 @@ dashboard.get('/tickets', async (c) => {
       .where(eq((tickets as any).userId, user.id))
       .orderBy(desc((tickets as any).createdAt))
   );
+
+  // Batch-fetch related events, payments, and invoices (avoids N+1 per ticket).
+  const eventIds = [...new Set(userTickets.map((t: any) => t.eventId).filter(Boolean))];
+  const ticketIds = userTickets.map((t: any) => t.id);
+
+  const eventRows = eventIds.length
+    ? await dbAll<any>((db as any).select().from(events).where(inArray((events as any).id, eventIds)))
+    : [];
+  const paymentRows = ticketIds.length
+    ? await dbAll<any>((db as any).select().from(payments).where(inArray((payments as any).ticketId, ticketIds)))
+    : [];
+
+  const eventsById = new Map(eventRows.map((e: any) => [e.id, e]));
+  const paymentsByTicketId = new Map(paymentRows.map((p: any) => [p.ticketId, p]));
+
+  const paidPaymentIds = paymentRows.filter((p: any) => p.status === 'paid').map((p: any) => p.id);
+  const invoiceRows = paidPaymentIds.length
+    ? await dbAll<any>((db as any).select().from(invoices).where(inArray((invoices as any).paymentId, paidPaymentIds)))
+    : [];
+  const invoicesByPaymentId = new Map(invoiceRows.map((inv: any) => [inv.paymentId, inv]));
   
-  // Get event details for each ticket
-  const ticketsWithEvents = await Promise.all(
-    userTickets.map(async (ticket: any) => {
-      const event = await dbGet<any>(
-        (db as any)
-          .select()
-          .from(events)
-          .where(eq((events as any).id, ticket.eventId))
-      );
-      
-      const payment = await dbGet<any>(
-        (db as any)
-          .select()
-          .from(payments)
-          .where(eq((payments as any).ticketId, ticket.id))
-      );
-      
-      // Check for invoice
-      let invoice: any = null;
-      if (payment && payment.status === 'paid') {
-        invoice = await dbGet<any>(
-          (db as any)
-            .select()
-            .from(invoices)
-            .where(eq((invoices as any).paymentId, payment.id))
-        );
-      }
+  const ticketsWithEvents = userTickets.map((ticket: any) => {
+      const event = eventsById.get(ticket.eventId);
+      const payment = paymentsByTicketId.get(ticket.id);
+      const invoice = payment && payment.status === 'paid' ? invoicesByPaymentId.get(payment.id) : null;
       
       return {
         ...ticket,
@@ -162,8 +161,7 @@ dashboard.get('/tickets', async (c) => {
           createdAt: invoice.createdAt,
         } : null,
       };
-    })
-  );
+    });
   
   return c.json({ tickets: ticketsWithEvents });
 });
@@ -452,13 +450,22 @@ dashboard.delete('/sessions/:id', async (c) => {
   return c.json({ message: 'Session revoked' });
 });
 
-// Revoke all sessions (logout everywhere)
+// Revoke all sessions (logout everywhere). Bumping the token version invalidates
+// every previously issued JWT for this user, which is the actual enforcement
+// mechanism (auth is stateless JWT, not DB-session based).
 dashboard.post('/sessions/revoke-all', async (c) => {
   const user = (c as any).get('user') as AuthUser;
   
   await invalidateAllUserSessions(user.id);
+  await bumpTokenVersion(user.id);
+
+  // Issue a fresh token so the current device stays signed in
+  const refreshed = await dbGet<any>(
+    (db as any).select().from(users).where(eq((users as any).id, user.id))
+  );
+  const token = await createToken(user.id, user.email, user.role, refreshed?.tokenVersion ?? 0);
   
-  return c.json({ message: 'All sessions revoked. Please log in again.' });
+  return c.json({ message: 'All other sessions revoked.', token });
 });
 
 // Set password (for users without one)
@@ -471,7 +478,7 @@ dashboard.post('/set-password', zValidator('json', setPasswordSchema), async (c)
   const { password } = c.req.valid('json');
   
   // Check if user already has a password
-  if (user.password) {
+  if (await getUserPasswordHash(user.id)) {
     return c.json({ error: 'Password already set. Use change password instead.' }, 400);
   }
   
@@ -502,7 +509,7 @@ dashboard.post('/unlink-google', async (c) => {
     return c.json({ error: 'Google account not linked' }, 400);
   }
   
-  if (!user.password) {
+  if (!(await getUserPasswordHash(user.id))) {
     return c.json({ error: 'Cannot unlink Google without a password set' }, 400);
   }
   
diff --git a/backend/src/routes/emails.ts b/backend/src/routes/emails.ts
index 281e900..68dd6c5 100644
--- a/backend/src/routes/emails.ts
+++ b/backend/src/routes/emails.ts
@@ -1,4 +1,6 @@
 import { Hono } from 'hono';
+import { zValidator } from '@hono/zod-validator';
+import { z } from 'zod';
 import { db, dbGet, dbAll, emailTemplates, emailLogs, events, tickets } from '../db/index.js';
 import { eq, desc, and, or, sql } from 'drizzle-orm';
 import { requireAuth } from '../lib/auth.js';
@@ -9,6 +11,50 @@ import { getQueueStatus } from '../lib/emailQueue.js';
 
 const emailsRouter = new Hono();
 
+const slugPattern = /^[a-z0-9-]+$/;
+
+const createTemplateSchema = z.object({
+  name: z.string().min(1).max(255),
+  slug: z.string().min(1).max(100).regex(slugPattern),
+  subject: z.string().min(1).max(500),
+  subjectEs: z.string().max(500).optional().nullable(),
+  bodyHtml: z.string().min(1).max(200_000),
+  bodyHtmlEs: z.string().max(200_000).optional().nullable(),
+  bodyText: z.string().max(200_000).optional().nullable(),
+  bodyTextEs: z.string().max(200_000).optional().nullable(),
+  description: z.string().max(2000).optional().nullable(),
+  variables: z.array(z.any()).max(100).optional(),
+});
+
+const updateTemplateSchema = createTemplateSchema.partial().extend({
+  isActive: z.boolean().optional(),
+});
+
+const sendCustomEmailSchema = z.object({
+  to: z.string().email().max(254),
+  toName: z.string().max(200).optional(),
+  subject: z.string().min(1).max(500),
+  bodyHtml: z.string().min(1).max(200_000),
+  bodyText: z.string().max(200_000).optional(),
+  eventId: z.string().optional(),
+});
+
+const emailLogsQuerySchema = z.object({
+  limit: z.coerce.number().int().min(1).max(100).optional().default(50),
+  offset: z.coerce.number().int().min(0).optional().default(0),
+});
+
+// Safely parse a stored JSON variables column; a corrupt row must not 500 the route.
+function safeParseVariables(raw: any): any[] {
+  if (!raw) return [];
+  try {
+    const parsed = JSON.parse(raw);
+    return Array.isArray(parsed) ? parsed : [];
+  } catch {
+    return [];
+  }
+}
+
 // ==================== Template Routes ====================
 
 // Get all email templates
@@ -20,7 +66,7 @@ emailsRouter.get('/templates', requireAuth(['admin', 'organizer']), async (c) =>
   // Parse variables JSON for each template
   const parsedTemplates = templates.map((t: any) => ({
     ...t,
-    variables: t.variables ? JSON.parse(t.variables) : [],
+    variables: safeParseVariables(t.variables),
     isSystem: Boolean(t.isSystem),
     isActive: Boolean(t.isActive),
   }));
@@ -46,7 +92,7 @@ emailsRouter.get('/templates/:id', requireAuth(['admin', 'organizer']), async (c
   return c.json({ 
     template: {
       ...template,
-      variables: template.variables ? JSON.parse(template.variables) : [],
+      variables: safeParseVariables(template.variables),
       isSystem: Boolean(template.isSystem),
       isActive: Boolean(template.isActive),
     }
@@ -54,14 +100,10 @@ emailsRouter.get('/templates/:id', requireAuth(['admin', 'organizer']), async (c
 });
 
 // Create new email template
-emailsRouter.post('/templates', requireAuth(['admin']), async (c) => {
-  const body = await c.req.json();
+emailsRouter.post('/templates', requireAuth(['admin']), zValidator('json', createTemplateSchema), async (c) => {
+  const body = c.req.valid('json');
   const { name, slug, subject, subjectEs, bodyHtml, bodyHtmlEs, bodyText, bodyTextEs, description, variables } = body;
   
-  if (!name || !slug || !subject || !bodyHtml) {
-    return c.json({ error: 'Name, slug, subject, and bodyHtml are required' }, 400);
-  }
-  
   // Check if slug already exists
   const existing = await dbGet<any>(
     (db as any).select().from(emailTemplates).where(eq((emailTemplates as any).slug, slug))
@@ -104,9 +146,9 @@ emailsRouter.post('/templates', requireAuth(['admin']), async (c) => {
 });
 
 // Update email template
-emailsRouter.put('/templates/:id', requireAuth(['admin']), async (c) => {
+emailsRouter.put('/templates/:id', requireAuth(['admin']), zValidator('json', updateTemplateSchema), async (c) => {
   const { id } = c.req.param();
-  const body = await c.req.json();
+  const body = c.req.valid('json');
   
   const existing = await dbGet<any>(
     (db as any)
@@ -130,13 +172,14 @@ emailsRouter.put('/templates/:id', requireAuth(['admin']), async (c) => {
   }
   
   for (const field of allowedFields) {
-    if (body[field] !== undefined) {
+    const value = (body as Record<string, unknown>)[field];
+    if (value !== undefined) {
       if (field === 'variables') {
-        updateData[field] = JSON.stringify(body[field]);
+        updateData[field] = JSON.stringify(value);
       } else if (field === 'isActive') {
-        updateData[field] = body[field] ? 1 : 0;
+        updateData[field] = value ? 1 : 0;
       } else {
-        updateData[field] = body[field];
+        updateData[field] = value;
       }
     }
   }
@@ -156,7 +199,7 @@ emailsRouter.put('/templates/:id', requireAuth(['admin']), async (c) => {
   return c.json({ 
     template: {
       ...updated,
-      variables: updated.variables ? JSON.parse(updated.variables) : [],
+      variables: safeParseVariables(updated.variables),
       isSystem: Boolean(updated.isSystem),
       isActive: Boolean(updated.isActive),
     },
@@ -203,16 +246,22 @@ emailsRouter.post('/send/event/:eventId', requireAuth(['admin', 'organizer']), a
   const body = await c.req.json();
   const { templateSlug, customVariables, recipientFilter } = body;
   
-  if (!templateSlug) {
+  if (!templateSlug || typeof templateSlug !== 'string') {
     return c.json({ error: 'Template slug is required' }, 400);
   }
+
+  const allowedFilters = ['confirmed', 'pending', 'all', 'checked_in'];
+  const filter = recipientFilter || 'confirmed';
+  if (!allowedFilters.includes(filter)) {
+    return c.json({ error: `Invalid recipientFilter. Allowed: ${allowedFilters.join(', ')}` }, 400);
+  }
   
   // Queue emails for background processing instead of sending synchronously
   const result = await emailService.queueEventEmails({
     eventId,
     templateSlug,
     customVariables,
-    recipientFilter: recipientFilter || 'confirmed',
+    recipientFilter: filter,
     sentBy: user?.id,
   });
   
@@ -220,14 +269,9 @@ emailsRouter.post('/send/event/:eventId', requireAuth(['admin', 'organizer']), a
 });
 
 // Send custom email to specific recipients
-emailsRouter.post('/send/custom', requireAuth(['admin', 'organizer']), async (c) => {
+emailsRouter.post('/send/custom', requireAuth(['admin', 'organizer']), zValidator('json', sendCustomEmailSchema), async (c) => {
   const user = (c as any).get('user');
-  const body = await c.req.json();
-  const { to, toName, subject, bodyHtml, bodyText, eventId } = body;
-  
-  if (!to || !subject || !bodyHtml) {
-    return c.json({ error: 'Recipient (to), subject, and bodyHtml are required' }, 400);
-  }
+  const { to, toName, subject, bodyHtml, bodyText, eventId } = c.req.valid('json');
   
   const result = await emailService.sendCustomEmail({
     to,
@@ -272,7 +316,7 @@ emailsRouter.post('/preview', requireAuth(['admin', 'organizer']), async (c) =>
     : template.bodyHtml;
   
   const finalSubject = replaceTemplateVariables(subject, allVariables);
-  const finalBodyContent = replaceTemplateVariables(bodyHtml, allVariables);
+  const finalBodyContent = replaceTemplateVariables(bodyHtml, allVariables, true);
   const finalBodyHtml = wrapInBaseTemplate(finalBodyContent, { ...allVariables, subject: finalSubject });
   
   return c.json({
@@ -288,8 +332,9 @@ emailsRouter.get('/logs', requireAuth(['admin', 'organizer']), async (c) => {
   const eventId = c.req.query('eventId');
   const status = c.req.query('status');
   const search = c.req.query('search');
-  const limit = parseInt(c.req.query('limit') || '50');
-  const offset = parseInt(c.req.query('offset') || '0');
+  // Clamp pagination so a NaN / out-of-range value can't produce undefined query behaviour.
+  const limit = Math.min(Math.max(parseInt(c.req.query('limit') || '50', 10) || 50, 1), 200);
+  const offset = Math.max(parseInt(c.req.query('offset') || '0', 10) || 0, 0);
   
   let query = (db as any).select().from(emailLogs);
   
diff --git a/backend/src/routes/events.ts b/backend/src/routes/events.ts
index c7ed4ad..8561381 100644
--- a/backend/src/routes/events.ts
+++ b/backend/src/routes/events.ts
@@ -127,8 +127,13 @@ const baseEventSchema = z.object({
   currency: z.string().default('PYG'),
   capacity: z.union([z.number(), z.string()]).transform((val) => typeof val === 'string' ? parseInt(val, 10) || 50 : val).pipe(z.number().min(1)).default(50),
   status: z.enum(['draft', 'published', 'unlisted', 'cancelled', 'completed', 'archived']).default('draft'),
-  // Accept relative paths (/uploads/...) or full URLs
-  bannerUrl: z.string().optional().nullable().or(z.literal('')),
+  // Accept relative paths (/uploads/...) or http(s) URLs only — reject schemes like
+  // javascript:/data: that could be reflected into an href/src on the frontend.
+  bannerUrl: z.string()
+    .refine((v) => v === '' || v.startsWith('/') || /^https?:\/\//i.test(v), {
+      message: 'Banner URL must be a relative path or an http(s) URL',
+    })
+    .optional().nullable().or(z.literal('')),
   // External booking support - accept boolean or number (0/1 from DB)
   externalBookingEnabled: z.union([z.boolean(), z.number()]).transform(normalizeBoolean).default(false),
   externalBookingUrl: z.string().url().optional().nullable().or(z.literal('')),
@@ -166,51 +171,59 @@ const updateEventSchema = baseEventSchema.partial().refine(
 eventsRouter.get('/', async (c) => {
   const status = c.req.query('status');
   const upcoming = c.req.query('upcoming');
-  
-  let query = (db as any).select().from(events);
-  
-  if (status) {
-    query = query.where(eq((events as any).status, status));
-  }
-  
+
+  // Only privileged users may see non-public events (drafts, archived, etc.).
+  // Anonymous/regular callers are restricted to published events regardless of
+  // any client-supplied status filter, so drafts cannot leak.
+  const authUser: any = await getAuthUser(c);
+  const isPrivileged = !!authUser && ['admin', 'organizer', 'staff', 'marketing'].includes(authUser.role);
+
+  const conditions: any[] = [];
+
   if (upcoming === 'true') {
-    const now = getNow();
-    query = query.where(
-      and(
-        eq((events as any).status, 'published'),
-        gte((events as any).startDatetime, now)
-      )
-    );
+    // Upcoming feed is always published + future-dated, for everyone.
+    conditions.push(eq((events as any).status, 'published'));
+    conditions.push(gte((events as any).startDatetime, getNow()));
+  } else if (isPrivileged) {
+    // Admins/staff may filter by any status (or list everything when unset).
+    if (status) {
+      conditions.push(eq((events as any).status, status));
+    }
+  } else {
+    // Public listing: published events only, regardless of any status param.
+    conditions.push(eq((events as any).status, 'published'));
+  }
+
+  let query = (db as any).select().from(events);
+  if (conditions.length > 0) {
+    query = query.where(conditions.length === 1 ? conditions[0] : and(...conditions));
   }
   
-  const result = await dbAll(query.orderBy(desc((events as any).startDatetime)));
-  
-  // Get ticket counts for each event
-  const eventsWithCounts = await Promise.all(
-    result.map(async (event: any) => {
-      // Count confirmed AND checked_in tickets (checked_in were previously confirmed)
-      // This ensures check-in doesn't affect capacity/spots_left
-      const ticketCount = await dbGet<any>(
-        (db as any)
-          .select({ count: sql<number>`count(*)` })
-          .from(tickets)
-          .where(
-            and(
-              eq((tickets as any).eventId, event.id),
-              sql`${(tickets as any).status} IN ('confirmed', 'checked_in')`
-            )
-          )
-      );
-      
-      const normalized = normalizeEvent(event);
-      const bookedCount = ticketCount?.count || 0;
-      return {
-        ...normalized,
-        bookedCount,
-        availableSeats: calculateAvailableSeats(normalized.capacity, bookedCount),
-      };
-    })
+  const result = await dbAll<any>(query.orderBy(desc((events as any).startDatetime)));
+
+  // Single grouped query for booked counts across all events (avoids N+1: previously
+  // this ran one COUNT query per event).
+  const countRows = await dbAll<any>(
+    (db as any)
+      .select({ eventId: (tickets as any).eventId, count: sql<number>`count(*)` })
+      .from(tickets)
+      .where(sql`${(tickets as any).status} IN ('confirmed', 'checked_in')`)
+      .groupBy((tickets as any).eventId)
   );
+  const countByEvent = new Map<string, number>();
+  for (const row of countRows) {
+    countByEvent.set(row.eventId, Number(row.count) || 0);
+  }
+
+  const eventsWithCounts = result.map((event: any) => {
+    const normalized = normalizeEvent(event);
+    const bookedCount = countByEvent.get(event.id) || 0;
+    return {
+      ...normalized,
+      bookedCount,
+      availableSeats: calculateAvailableSeats(normalized.capacity, bookedCount),
+    };
+  });
   
   return c.json({ events: eventsWithCounts });
 });
@@ -223,6 +236,15 @@ eventsRouter.get('/:id', async (c) => {
   if (!event) {
     return c.json({ error: 'Event not found' }, 404);
   }
+
+  // Draft events are only visible to privileged users (admin preview); hide from public.
+  if ((event as any).status === 'draft') {
+    const authUser: any = await getAuthUser(c);
+    const isPrivileged = !!authUser && ['admin', 'organizer', 'staff', 'marketing'].includes(authUser.role);
+    if (!isPrivileged) {
+      return c.json({ error: 'Event not found' }, 404);
+    }
+  }
   
   // Count confirmed AND checked_in tickets (checked_in were previously confirmed)
   // This ensures check-in doesn't affect capacity/spots_left
diff --git a/backend/src/routes/faq.ts b/backend/src/routes/faq.ts
index 86f5b2f..67b7370 100644
--- a/backend/src/routes/faq.ts
+++ b/backend/src/routes/faq.ts
@@ -6,6 +6,22 @@ import { getNow, generateId } from '../lib/utils.js';
 
 const faqRouter = new Hono();
 
+// Upper bounds for admin-supplied FAQ content (guards against accidental/abusive huge payloads)
+const MAX_QUESTION_LEN = 1000;
+const MAX_ANSWER_LEN = 20000;
+
+// Returns an error message if any provided field exceeds its limit, else null.
+function faqLengthError(fields: { question?: any; questionEs?: any; answer?: any; answerEs?: any }): string | null {
+  const check = (v: any, max: number, label: string) =>
+    typeof v === 'string' && v.length > max ? `${label} must be at most ${max} characters` : null;
+  return (
+    check(fields.question, MAX_QUESTION_LEN, 'Question') ||
+    check(fields.questionEs, MAX_QUESTION_LEN, 'Question (ES)') ||
+    check(fields.answer, MAX_ANSWER_LEN, 'Answer') ||
+    check(fields.answerEs, MAX_ANSWER_LEN, 'Answer (ES)')
+  );
+}
+
 // ==================== Public Routes ====================
 
 // Get FAQ list for public (only enabled; optional filter for homepage)
@@ -98,6 +114,11 @@ faqRouter.post('/admin', requireAuth(['admin']), async (c) => {
     return c.json({ error: 'Question and answer (EN) are required' }, 400);
   }
 
+  const lengthError = faqLengthError({ question, questionEs, answer, answerEs });
+  if (lengthError) {
+    return c.json({ error: lengthError }, 400);
+  }
+
   const now = getNow();
   const id = generateId();
 
@@ -157,6 +178,11 @@ faqRouter.put('/admin/:id', requireAuth(['admin']), async (c) => {
     return c.json({ error: 'FAQ not found' }, 404);
   }
 
+  const lengthError = faqLengthError({ question, questionEs, answer, answerEs });
+  if (lengthError) {
+    return c.json({ error: lengthError }, 400);
+  }
+
   const updateData: Record<string, unknown> = {
     updatedAt: getNow(),
   };
@@ -209,6 +235,15 @@ faqRouter.post('/admin/reorder', requireAuth(['admin']), async (c) => {
     return c.json({ error: 'ids array is required' }, 400);
   }
 
+  // Verify every id exists before applying ranks (prevents silent no-ops on bad input).
+  const existingRows = await dbAll<any>(
+    (db as any).select({ id: (faqQuestions as any).id }).from(faqQuestions)
+  );
+  const existingIds = new Set(existingRows.map((r: any) => r.id));
+  if (ids.some((id: string) => !existingIds.has(id))) {
+    return c.json({ error: 'One or more FAQ ids are invalid' }, 400);
+  }
+
   const now = getNow();
   for (let i = 0; i < ids.length; i++) {
     await (db as any)
diff --git a/backend/src/routes/legal-pages.ts b/backend/src/routes/legal-pages.ts
index 321071f..6132094 100644
--- a/backend/src/routes/legal-pages.ts
+++ b/backend/src/routes/legal-pages.ts
@@ -162,6 +162,13 @@ legalPagesRouter.get('/', async (c) => {
 legalPagesRouter.get('/:slug', async (c) => {
   const { slug } = c.req.param();
   const locale = c.req.query('locale') || 'en';
+
+  // Reject anything that isn't a simple slug. The filesystem fallback below builds a
+  // path from this value, so an unconstrained slug (e.g. "../../etc/passwd") would
+  // allow path traversal / arbitrary file reads.
+  if (!/^[a-z0-9-]+$/.test(slug)) {
+    return c.json({ error: 'Legal page not found' }, 404);
+  }
   
   // First try to get from database
   const page = await dbGet<any>(
@@ -275,6 +282,17 @@ legalPagesRouter.put('/admin/:slug', requireAuth(['admin']), async (c) => {
   if (!enContent && !esContent) {
     return c.json({ error: 'At least one language content is required' }, 400);
   }
+
+  // Bound the sizes of admin-supplied content to avoid unbounded payloads.
+  const MAX_CONTENT_LEN = 200000; // ~200 KB of markdown per language
+  const MAX_TITLE_LEN = 255;
+  const tooLong = (v: any, max: number) => typeof v === 'string' && v.length > max;
+  if (tooLong(enContent, MAX_CONTENT_LEN) || tooLong(esContent, MAX_CONTENT_LEN)) {
+    return c.json({ error: `Content must be at most ${MAX_CONTENT_LEN} characters` }, 400);
+  }
+  if (tooLong(title, MAX_TITLE_LEN) || tooLong(titleEs, MAX_TITLE_LEN)) {
+    return c.json({ error: `Title must be at most ${MAX_TITLE_LEN} characters` }, 400);
+  }
   
   const existing = await dbGet(
     (db as any)
diff --git a/backend/src/routes/lnbits.ts b/backend/src/routes/lnbits.ts
index b433b33..ce29569 100644
--- a/backend/src/routes/lnbits.ts
+++ b/backend/src/routes/lnbits.ts
@@ -1,7 +1,7 @@
 import { Hono } from 'hono';
 import { streamSSE } from 'hono/streaming';
 import { db, dbGet, dbAll, tickets, payments } from '../db/index.js';
-import { eq } from 'drizzle-orm';
+import { eq, and } from 'drizzle-orm';
 import { getNow } from '../lib/utils.js';
 import { verifyWebhookPayment, getPaymentStatus } from '../lib/lnbits.js';
 import emailService from '../lib/email.js';
@@ -111,13 +111,23 @@ function stopBackgroundChecker(ticketId: string) {
  */
 lnbitsRouter.post('/webhook', async (c) => {
   try {
+    // Optional shared-secret gate: if LNBITS_WEBHOOK_SECRET is configured, the
+    // webhook URL must carry a matching ?token=... (set when the invoice is created).
+    const webhookSecret = process.env.LNBITS_WEBHOOK_SECRET || '';
+    if (webhookSecret) {
+      const provided = c.req.query('token') || c.req.header('x-webhook-secret') || '';
+      if (provided !== webhookSecret) {
+        console.warn('LNbits webhook rejected: invalid or missing secret');
+        return c.json({ received: true, processed: false }, 401);
+      }
+    }
+
     const payload: LNbitsWebhookPayload = await c.req.json();
     
+    // Log identifiers only (no full payload / PII)
     console.log('LNbits webhook received:', {
       paymentHash: payload.payment_hash,
       status: payload.status,
-      amount: payload.amount,
-      extra: payload.extra,
     });
 
     // Verify the payment is actually complete by checking with LNbits
@@ -135,6 +145,20 @@ lnbitsRouter.post('/webhook', async (c) => {
       return c.json({ received: true, processed: false }, 200);
     }
 
+    // CRITICAL: bind the paid hash to this ticket's own invoice. Without this, a
+    // valid paid hash from any other invoice could be replayed with an arbitrary
+    // ticketId to confirm tickets for free.
+    const ticketPayment = await dbGet<any>(
+      (db as any).select().from(payments).where(eq((payments as any).ticketId, ticketId))
+    );
+    if (!ticketPayment || ticketPayment.reference !== payload.payment_hash) {
+      console.warn('LNbits webhook rejected: payment hash does not match the ticket invoice', {
+        ticketId,
+        paymentHash: payload.payment_hash,
+      });
+      return c.json({ received: true, processed: false }, 200);
+    }
+
     // Stop background checker since webhook confirmed payment
     stopBackgroundChecker(ticketId);
 
@@ -186,15 +210,13 @@ async function handlePaymentComplete(ticketId: string, paymentHash: string) {
     console.log(`Multi-ticket booking detected: ${ticketsToConfirm.length} tickets to confirm`);
   }
   
-  // Confirm all tickets in the booking
+  // Confirm all tickets in the booking (idempotent: only flip pending -> confirmed)
   for (const ticket of ticketsToConfirm) {
-    // Update ticket status to confirmed
     await (db as any)
       .update(tickets)
       .set({ status: 'confirmed' })
-      .where(eq((tickets as any).id, ticket.id));
+      .where(and(eq((tickets as any).id, ticket.id), eq((tickets as any).status, 'pending')));
     
-    // Update payment status to paid
     await (db as any)
       .update(payments)
       .set({ 
@@ -203,7 +225,7 @@ async function handlePaymentComplete(ticketId: string, paymentHash: string) {
         paidAt: now,
         updatedAt: now,
       })
-      .where(eq((payments as any).ticketId, ticket.id));
+      .where(and(eq((payments as any).ticketId, ticket.id), eq((payments as any).status, 'pending')));
     
     console.log(`Ticket ${ticket.id} confirmed via Lightning payment (hash: ${paymentHash})`);
   }
diff --git a/backend/src/routes/media.ts b/backend/src/routes/media.ts
index b0b75b6..a2af83e 100644
--- a/backend/src/routes/media.ts
+++ b/backend/src/routes/media.ts
@@ -1,19 +1,56 @@
 import { Hono } from 'hono';
 import { db, dbGet, dbAll, media } from '../db/index.js';
-import { eq } from 'drizzle-orm';
+import { eq, and } from 'drizzle-orm';
 import { requireAuth } from '../lib/auth.js';
 import { generateId, getNow } from '../lib/utils.js';
 import { writeFile, mkdir, unlink } from 'fs/promises';
 import { existsSync } from 'fs';
-import { join, extname } from 'path';
+import { join } from 'path';
 
 const mediaRouter = new Hono();
 
 const UPLOAD_DIR = './uploads';
-const ALLOWED_TYPES = ['image/jpeg', 'image/png', 'image/gif', 'image/webp', 'image/avif'];
 const MAX_FILE_SIZE =
   (Number(process.env.MEDIA_MAX_UPLOAD_MB || '10') || 10) * 1024 * 1024; // default 10MB
 
+/**
+ * Detect a real image type from the file's magic bytes (content sniffing).
+ * Returns the canonical mime + extension, or null if the content is not an
+ * allowed image. We deliberately ignore the client-supplied filename and
+ * Content-Type so an attacker cannot store e.g. an .html/.svg payload.
+ */
+function detectImageType(buf: Buffer): { mime: string; ext: string } | null {
+  if (buf.length < 12) return null;
+
+  // JPEG: FF D8 FF
+  if (buf[0] === 0xff && buf[1] === 0xd8 && buf[2] === 0xff) {
+    return { mime: 'image/jpeg', ext: '.jpg' };
+  }
+  // PNG: 89 50 4E 47 0D 0A 1A 0A
+  if (
+    buf[0] === 0x89 && buf[1] === 0x50 && buf[2] === 0x4e && buf[3] === 0x47 &&
+    buf[4] === 0x0d && buf[5] === 0x0a && buf[6] === 0x1a && buf[7] === 0x0a
+  ) {
+    return { mime: 'image/png', ext: '.png' };
+  }
+  // GIF: "GIF87a" / "GIF89a"
+  if (buf.toString('ascii', 0, 6) === 'GIF87a' || buf.toString('ascii', 0, 6) === 'GIF89a') {
+    return { mime: 'image/gif', ext: '.gif' };
+  }
+  // WEBP: "RIFF"...."WEBP"
+  if (buf.toString('ascii', 0, 4) === 'RIFF' && buf.toString('ascii', 8, 12) === 'WEBP') {
+    return { mime: 'image/webp', ext: '.webp' };
+  }
+  // AVIF / HEIF: "....ftyp" with an avif/heic brand
+  if (buf.toString('ascii', 4, 8) === 'ftyp') {
+    const brand = buf.toString('ascii', 8, 12);
+    if (brand === 'avif' || brand === 'avis') {
+      return { mime: 'image/avif', ext: '.avif' };
+    }
+  }
+  return null;
+}
+
 // Ensure upload directory exists
 async function ensureUploadDir() {
   if (!existsSync(UPLOAD_DIR)) {
@@ -31,28 +68,30 @@ mediaRouter.post('/upload', requireAuth(['admin', 'organizer']), async (c) => {
       return c.json({ error: 'No file provided' }, 400);
     }
     
-    // Validate file type
-    if (!ALLOWED_TYPES.includes(file.type)) {
-      return c.json({ error: 'Invalid file type. Allowed: JPEG, PNG, GIF, WebP, AVIF' }, 400);
-    }
-    
-    // Validate file size
+    // Validate file size (cheap check before reading the whole buffer)
     if (file.size > MAX_FILE_SIZE) {
       const mb = Math.round((MAX_FILE_SIZE / (1024 * 1024)) * 10) / 10;
       return c.json({ error: `File too large. Maximum size: ${mb}MB` }, 400);
     }
     
+    // Read the bytes and validate the *content* (not the client-provided type/name)
+    const arrayBuffer = await file.arrayBuffer();
+    const buffer = Buffer.from(arrayBuffer);
+
+    const detected = detectImageType(buffer);
+    if (!detected) {
+      return c.json({ error: 'Invalid file. Allowed: JPEG, PNG, GIF, WebP, AVIF' }, 400);
+    }
+    
     await ensureUploadDir();
     
-    // Generate unique filename
+    // Generate unique filename using the *detected* extension (ignore client filename)
     const id = generateId();
-    const ext = extname(file.name) || '.jpg';
-    const filename = `${id}${ext}`;
+    const filename = `${id}${detected.ext}`;
     const filepath = join(UPLOAD_DIR, filename);
     
     // Write file
-    const arrayBuffer = await file.arrayBuffer();
-    await writeFile(filepath, Buffer.from(arrayBuffer));
+    await writeFile(filepath, buffer);
     
     // Get related info from form data
     const relatedId = body['relatedId'] as string | undefined;
@@ -128,17 +167,20 @@ mediaRouter.delete('/:id', requireAuth(['admin', 'organizer']), async (c) => {
 mediaRouter.get('/', requireAuth(['admin', 'organizer']), async (c) => {
   const relatedType = c.req.query('relatedType');
   const relatedId = c.req.query('relatedId');
+  const limit = Math.min(Math.max(parseInt(c.req.query('limit') || '200', 10) || 200, 1), 500);
+  const offset = Math.max(parseInt(c.req.query('offset') || '0', 10) || 0, 0);
   
+  // Combine filters into a single where() — chaining .where() replaces the prior condition in Drizzle.
+  const conditions: any[] = [];
+  if (relatedType) conditions.push(eq((media as any).relatedType, relatedType));
+  if (relatedId) conditions.push(eq((media as any).relatedId, relatedId));
+
   let query = (db as any).select().from(media);
-  
-  if (relatedType) {
-    query = query.where(eq((media as any).relatedType, relatedType));
-  }
-  if (relatedId) {
-    query = query.where(eq((media as any).relatedId, relatedId));
+  if (conditions.length > 0) {
+    query = query.where(conditions.length === 1 ? conditions[0] : and(...conditions));
   }
   
-  const result = await dbAll(query);
+  const result = await dbAll(query.limit(limit).offset(offset));
   
   return c.json({ media: result });
 });
diff --git a/backend/src/routes/payment-options.ts b/backend/src/routes/payment-options.ts
index 33fd275..27b4496 100644
--- a/backend/src/routes/payment-options.ts
+++ b/backend/src/routes/payment-options.ts
@@ -1,9 +1,9 @@
 import { Hono } from 'hono';
 import { zValidator } from '@hono/zod-validator';
 import { z } from 'zod';
-import { db, dbGet, paymentOptions, eventPaymentOverrides, events } from '../db/index.js';
+import { db, dbGet, paymentOptions, eventPaymentOverrides, events, tickets } from '../db/index.js';
 import { eq } from 'drizzle-orm';
-import { requireAuth } from '../lib/auth.js';
+import { requireAuth, getAuthUser } from '../lib/auth.js';
 import { generateId, getNow, convertBooleansForDb } from '../lib/utils.js';
 
 const paymentOptionsRouter = new Hono();
@@ -40,6 +40,23 @@ const updatePaymentOptionsSchema = z.object({
   allowDuplicateBookings: booleanOrNumber.optional(),
 });
 
+/** Strip bank account numbers from payment options for anonymous callers. */
+function publicPaymentOptions(merged: Record<string, any>) {
+  return {
+    ...merged,
+    bankName: null,
+    bankAccountHolder: null,
+    bankAccountNumber: null,
+    bankAlias: null,
+    bankPhone: null,
+    tpagoLink: null,
+    tpagoLink2: null,
+    tpagoLink3: null,
+    tpagoLink4: null,
+    tpagoLink5: null,
+  };
+}
+
 // Schema for event-level overrides
 const updateEventOverridesSchema = z.object({
   tpagoEnabled: booleanOrNumber.optional().nullable(),
@@ -151,6 +168,7 @@ paymentOptionsRouter.put('/', requireAuth(['admin']), zValidator('json', updateP
 // Get payment options for a specific event (merged with global)
 paymentOptionsRouter.get('/event/:eventId', async (c) => {
   const eventId = c.req.param('eventId');
+  const ticketId = c.req.query('ticketId');
 
   // Get the event first to verify it exists
   const event = await dbGet(
@@ -229,8 +247,24 @@ paymentOptionsRouter.get('/event/:eventId', async (c) => {
     cashInstructionsEs: overrides?.cashInstructionsEs ?? global.cashInstructionsEs,
   };
 
+  // Full bank/TPago credentials are only returned when the caller proves they hold
+  // a valid ticket for this event (the ticket UUID is the booking capability token),
+  // or when an authenticated admin/organizer requests them.
+  let revealSensitive = false;
+  const authUser: any = await getAuthUser(c);
+  if (authUser && ['admin', 'organizer'].includes(authUser.role)) {
+    revealSensitive = true;
+  } else if (ticketId) {
+    const ticket = await dbGet<any>(
+      (db as any).select().from(tickets).where(eq((tickets as any).id, ticketId))
+    );
+    if (ticket && ticket.eventId === eventId && ticket.status !== 'cancelled') {
+      revealSensitive = true;
+    }
+  }
+
   return c.json({
-    paymentOptions: merged,
+    paymentOptions: revealSensitive ? merged : publicPaymentOptions(merged),
     hasOverrides: !!overrides,
   });
 });
diff --git a/backend/src/routes/payments.ts b/backend/src/routes/payments.ts
index cd60ebe..f480479 100644
--- a/backend/src/routes/payments.ts
+++ b/backend/src/routes/payments.ts
@@ -162,6 +162,29 @@ paymentsRouter.get('/pending-approval', requireAuth(['admin', 'organizer']), asy
   return c.json({ payments: enrichedPayments });
 });
 
+// Get payment statistics (admin) — registered before /:id so "stats" is not parsed as an id
+paymentsRouter.get('/stats/overview', requireAuth(['admin']), async (c) => {
+  const [totalRow, pendingRow, paidRow, refundedRow, failedRow, revenueRow] = await Promise.all([
+    dbGet<any>((db as any).select({ count: sql<number>`count(*)` }).from(payments)),
+    dbGet<any>((db as any).select({ count: sql<number>`count(*)` }).from(payments).where(eq((payments as any).status, 'pending'))),
+    dbGet<any>((db as any).select({ count: sql<number>`count(*)` }).from(payments).where(eq((payments as any).status, 'paid'))),
+    dbGet<any>((db as any).select({ count: sql<number>`count(*)` }).from(payments).where(eq((payments as any).status, 'refunded'))),
+    dbGet<any>((db as any).select({ count: sql<number>`count(*)` }).from(payments).where(eq((payments as any).status, 'failed'))),
+    dbGet<any>((db as any).select({ total: sql<number>`COALESCE(SUM(${(payments as any).amount}), 0)` }).from(payments).where(eq((payments as any).status, 'paid'))),
+  ]);
+
+  return c.json({
+    stats: {
+      total: Number(totalRow?.count || 0),
+      pending: Number(pendingRow?.count || 0),
+      paid: Number(paidRow?.count || 0),
+      refunded: Number(refundedRow?.count || 0),
+      failed: Number(failedRow?.count || 0),
+      totalRevenue: Number(revenueRow?.total || 0),
+    },
+  });
+});
+
 // Get payment by ID (admin)
 paymentsRouter.get('/:id', requireAuth(['admin', 'organizer']), async (c) => {
   const id = c.req.param('id');
@@ -387,26 +410,40 @@ paymentsRouter.post('/:id/reject', requireAuth(['admin', 'organizer']), zValidat
   }
   
   const now = getNow();
-  
-  // Update payment status to failed
-  await (db as any)
-    .update(payments)
-    .set({ 
-      status: 'failed',
-      paidByAdminId: user.id,
-      adminNote: adminNote || payment.adminNote,
-      updatedAt: now,
-    })
-    .where(eq((payments as any).id, id));
-  
-  // Cancel the ticket - booking is no longer valid after rejection
-  await (db as any)
-    .update(tickets)
-    .set({ 
-      status: 'cancelled',
-      updatedAt: now,
-    })
-    .where(eq((tickets as any).id, payment.ticketId));
+
+  // Determine all tickets in this booking (multi-ticket bookings must be rejected together)
+  const rejectTicket = await dbGet<any>(
+    (db as any).select().from(tickets).where(eq((tickets as any).id, payment.ticketId))
+  );
+  let ticketsToReject: any[] = rejectTicket ? [rejectTicket] : [];
+  if (rejectTicket?.bookingId) {
+    ticketsToReject = await dbAll<any>(
+      (db as any).select().from(tickets).where(eq((tickets as any).bookingId, rejectTicket.bookingId))
+    );
+    console.log(`[Payment] Rejecting multi-ticket booking: ${rejectTicket.bookingId}, ${ticketsToReject.length} tickets`);
+  }
+
+  for (const t of ticketsToReject) {
+    // Fail the payment for each ticket in the booking
+    await (db as any)
+      .update(payments)
+      .set({ 
+        status: 'failed',
+        paidByAdminId: user.id,
+        adminNote: adminNote || payment.adminNote,
+        updatedAt: now,
+      })
+      .where(eq((payments as any).ticketId, (t as any).id));
+
+    // Cancel the ticket - booking is no longer valid after rejection
+    await (db as any)
+      .update(tickets)
+      .set({ 
+        status: 'cancelled',
+        updatedAt: now,
+      })
+      .where(eq((tickets as any).id, (t as any).id));
+  }
   
   // Send rejection email asynchronously (for manual payment methods only, if sendEmail is true)
   if (sendEmail !== false && ['bank_transfer', 'tpago'].includes(payment.provider)) {
@@ -529,56 +566,42 @@ paymentsRouter.post('/:id/refund', requireAuth(['admin']), async (c) => {
   }
   
   const now = getNow();
-  
-  // Update payment status
-  await (db as any)
-    .update(payments)
-    .set({ status: 'refunded', updatedAt: now })
-    .where(eq((payments as any).id, id));
-  
-  // Cancel associated ticket
-  await (db as any)
-    .update(tickets)
-    .set({ status: 'cancelled' })
-    .where(eq((tickets as any).id, payment.ticketId));
+
+  // Refund all tickets/payments in the booking (multi-ticket bookings refund together)
+  const refundTicket = await dbGet<any>(
+    (db as any).select().from(tickets).where(eq((tickets as any).id, payment.ticketId))
+  );
+  let ticketsToRefund: any[] = refundTicket ? [refundTicket] : [];
+  if (refundTicket?.bookingId) {
+    ticketsToRefund = await dbAll<any>(
+      (db as any).select().from(tickets).where(eq((tickets as any).bookingId, refundTicket.bookingId))
+    );
+    console.log(`[Payment] Refunding multi-ticket booking: ${refundTicket.bookingId}, ${ticketsToRefund.length} tickets`);
+  }
+
+  for (const t of ticketsToRefund) {
+    // Only refund payments that were actually paid; leave others untouched
+    await (db as any)
+      .update(payments)
+      .set({ status: 'refunded', updatedAt: now })
+      .where(and(eq((payments as any).ticketId, (t as any).id), eq((payments as any).status, 'paid')));
+
+    await (db as any)
+      .update(tickets)
+      .set({ status: 'cancelled' })
+      .where(eq((tickets as any).id, (t as any).id));
+  }
   
   return c.json({ message: 'Refund processed successfully' });
 });
 
 // Payment webhook (for Stripe/MercadoPago)
+// Not implemented: there is deliberately NO status mutation here. Until provider
+// signature verification is implemented, accepting webhooks would let anyone forge
+// a "paid" status. Returns 501 and never updates payments/tickets.
 paymentsRouter.post('/webhook', async (c) => {
-  // This would handle webhook notifications from payment providers
-  // Implementation depends on which provider is used
-  
-  const body = await c.req.json();
-  
-  // Log webhook for debugging
-  console.log('Payment webhook received:', body);
-  
-  // TODO: Implement provider-specific webhook handling
-  // - Verify webhook signature
-  // - Update payment status
-  // - Update ticket status
-  
-  return c.json({ received: true });
-});
-
-// Get payment statistics (admin)
-paymentsRouter.get('/stats/overview', requireAuth(['admin']), async (c) => {
-  const allPayments = await dbAll<any>((db as any).select().from(payments));
-  
-  const stats = {
-    total: allPayments.length,
-    pending: allPayments.filter((p: any) => p.status === 'pending').length,
-    paid: allPayments.filter((p: any) => p.status === 'paid').length,
-    refunded: allPayments.filter((p: any) => p.status === 'refunded').length,
-    failed: allPayments.filter((p: any) => p.status === 'failed').length,
-    totalRevenue: allPayments
-      .filter((p: any) => p.status === 'paid')
-      .reduce((sum: number, p: any) => sum + Number(p.amount || 0), 0),
-  };
-  
-  return c.json({ stats });
+  console.warn('Payment webhook received but provider webhooks are not implemented (no signature verification).');
+  return c.json({ error: 'Webhook handling is not implemented' }, 501);
 });
 
 export default paymentsRouter;
diff --git a/backend/src/routes/site-settings.ts b/backend/src/routes/site-settings.ts
index 5ff0592..e8a1389 100644
--- a/backend/src/routes/site-settings.ts
+++ b/backend/src/routes/site-settings.ts
@@ -17,9 +17,20 @@ interface UserContext {
 const siteSettingsRouter = new Hono<{ Variables: { user: UserContext } }>();
 
 // Validation schema for updating site settings
+// Validate against the runtime's IANA timezone database (rejects arbitrary strings
+// that later get fed into Intl.DateTimeFormat on the frontend).
+const isValidTimezone = (tz: string): boolean => {
+  try {
+    Intl.DateTimeFormat('en-US', { timeZone: tz });
+    return true;
+  } catch {
+    return false;
+  }
+};
+
 const updateSiteSettingsSchema = z.object({
-  timezone: z.string().optional(),
-  siteName: z.string().optional(),
+  timezone: z.string().refine(isValidTimezone, { message: 'Invalid timezone' }).optional(),
+  siteName: z.string().max(255).optional(),
   siteDescription: z.string().optional().nullable(),
   siteDescriptionEs: z.string().optional().nullable(),
   contactEmail: z.string().email().optional().nullable().or(z.literal('')),
diff --git a/backend/src/routes/tickets.ts b/backend/src/routes/tickets.ts
index 611dcc3..007e6b4 100644
--- a/backend/src/routes/tickets.ts
+++ b/backend/src/routes/tickets.ts
@@ -1,11 +1,12 @@
 import { Hono } from 'hono';
 import { zValidator } from '@hono/zod-validator';
 import { z } from 'zod';
-import { db, dbGet, dbAll, tickets, events, users, payments, paymentOptions, siteSettings } from '../db/index.js';
+import { db, dbGet, dbAll, tickets, events, users, payments, paymentOptions, eventPaymentOverrides, siteSettings, isSqlite } from '../db/index.js';
 import { eq, and, or, sql, inArray } from 'drizzle-orm';
 import { requireAuth, getAuthUser } from '../lib/auth.js';
 import { generateId, generateTicketCode, getNow, calculateAvailableSeats, isEventSoldOut } from '../lib/utils.js';
 import { createInvoice, isLNbitsConfigured } from '../lib/lnbits.js';
+import { rateLimitMiddleware } from '../lib/rateLimit.js';
 import emailService from '../lib/email.js';
 import { generateTicketPDF, generateCombinedTicketsPDF } from '../lib/pdf.js';
 
@@ -17,6 +18,9 @@ const attendeeSchema = z.object({
   lastName: z.string().min(2).optional().or(z.literal('')),
 });
 
+// Maximum tickets a single buyer can book at once (enforced server-side)
+const MAX_TICKETS_PER_BOOKING = 5;
+
 const createTicketSchema = z.object({
   eventId: z.string(),
   firstName: z.string().min(2),
@@ -24,12 +28,30 @@ const createTicketSchema = z.object({
   email: z.string().email(),
   phone: z.string().min(6).optional().or(z.literal('')),
   preferredLanguage: z.enum(['en', 'es']).optional(),
-  paymentMethod: z.enum(['bancard', 'lightning', 'cash', 'bank_transfer', 'tpago']).default('cash'),
+  // 'bancard' intentionally excluded: no checkout integration exists for it
+  paymentMethod: z.enum(['lightning', 'cash', 'bank_transfer', 'tpago']).default('cash'),
   ruc: z.string().regex(/^\d{6,10}$/, 'Invalid RUC format').optional().or(z.literal('')),
-  // Optional: array of attendees for multi-ticket booking
-  attendees: z.array(attendeeSchema).optional(),
+  // Optional: array of attendees for multi-ticket booking (capped at MAX_TICKETS_PER_BOOKING)
+  attendees: z.array(attendeeSchema).min(1).max(MAX_TICKETS_PER_BOOKING).optional(),
 });
 
+// Maps a payment provider to the merged payment-option flag that enables it
+function isPaymentMethodEnabled(method: string, merged: Record<string, any>): boolean {
+  const truthy = (v: any) => v === true || v === 1;
+  switch (method) {
+    case 'tpago':
+      return truthy(merged.tpagoEnabled);
+    case 'bank_transfer':
+      return truthy(merged.bankTransferEnabled);
+    case 'lightning':
+      return truthy(merged.lightningEnabled);
+    case 'cash':
+      return truthy(merged.cashEnabled);
+    default:
+      return false;
+  }
+}
+
 const updateTicketSchema = z.object({
   status: z.enum(['pending', 'confirmed', 'cancelled', 'checked_in']).optional(),
   adminNote: z.string().optional(),
@@ -60,6 +82,11 @@ ticketsRouter.post('/', zValidator('json', createTicketSchema), async (c) => {
     : [{ firstName: data.firstName, lastName: data.lastName }];
   
   const ticketCount = attendeesList.length;
+
+  // Enforce the per-booking ticket cap server-side (UI also caps, but the API is authoritative)
+  if (ticketCount < 1 || ticketCount > MAX_TICKETS_PER_BOOKING) {
+    return c.json({ error: `You can book between 1 and ${MAX_TICKETS_PER_BOOKING} tickets per order.` }, 400);
+  }
   
   // Get event
   const event = await dbGet<any>(
@@ -72,9 +99,28 @@ ticketsRouter.post('/', zValidator('json', createTicketSchema), async (c) => {
   if (!['published', 'unlisted'].includes(event.status)) {
     return c.json({ error: 'Event is not available for booking' }, 400);
   }
+
+  // Validate the requested payment method is actually enabled for this event
+  // (merge global options with any event-level overrides; override wins when not null)
+  const globalPaymentOptions = await dbGet<any>(
+    (db as any).select().from(paymentOptions)
+  );
+  const eventOverrides = await dbGet<any>(
+    (db as any).select().from(eventPaymentOverrides).where(eq((eventPaymentOverrides as any).eventId, data.eventId))
+  );
+  const mergedPaymentOptions: Record<string, any> = {
+    tpagoEnabled: eventOverrides?.tpagoEnabled ?? globalPaymentOptions?.tpagoEnabled ?? false,
+    bankTransferEnabled: eventOverrides?.bankTransferEnabled ?? globalPaymentOptions?.bankTransferEnabled ?? false,
+    lightningEnabled: eventOverrides?.lightningEnabled ?? globalPaymentOptions?.lightningEnabled ?? true,
+    cashEnabled: eventOverrides?.cashEnabled ?? globalPaymentOptions?.cashEnabled ?? true,
+  };
+  if (!isPaymentMethodEnabled(data.paymentMethod, mergedPaymentOptions)) {
+    return c.json({ error: 'Selected payment method is not available for this event' }, 400);
+  }
   
-  // Check capacity - count confirmed AND checked_in tickets
-  // (checked_in were previously confirmed, check-in doesn't affect capacity)
+  // Check capacity - count pending, confirmed AND checked_in tickets.
+  // Pending reservations must hold seats to prevent overselling via unpaid bookings
+  // (cancelled/failed tickets are excluded so abandoned/rejected bookings free their seats).
   const existingTicketCount = await dbGet<any>(
     (db as any)
       .select({ count: sql<number>`count(*)` })
@@ -82,7 +128,7 @@ ticketsRouter.post('/', zValidator('json', createTicketSchema), async (c) => {
       .where(
         and(
           eq((tickets as any).eventId, data.eventId),
-          sql`${(tickets as any).status} IN ('confirmed', 'checked_in')`
+          sql`${(tickets as any).status} IN ('pending', 'confirmed', 'checked_in')`
         )
       )
   );
@@ -128,13 +174,7 @@ ticketsRouter.post('/', zValidator('json', createTicketSchema), async (c) => {
   }
   
   // Check for duplicate booking (unless allowDuplicateBookings is enabled)
-  const globalOptions = await dbGet<any>(
-    (db as any)
-      .select()
-      .from(paymentOptions)
-  );
-  
-  const allowDuplicateBookings = globalOptions?.allowDuplicateBookings ?? false;
+  const allowDuplicateBookings = globalPaymentOptions?.allowDuplicateBookings ?? false;
   
   if (!allowDuplicateBookings) {
     const existingTicket = await dbGet<any>(
@@ -156,52 +196,151 @@ ticketsRouter.post('/', zValidator('json', createTicketSchema), async (c) => {
   
   // Generate booking ID to group multiple tickets
   const bookingId = generateId();
-  
-  // Create tickets for each attendee
-  const createdTickets: any[] = [];
-  const createdPayments: any[] = [];
-  
-  for (let i = 0; i < attendeesList.length; i++) {
-    const attendee = attendeesList[i];
-    const ticketId = generateId();
-    const qrCode = generateTicketCode();
-    
-    const newTicket = {
-      id: ticketId,
-      bookingId: ticketCount > 1 ? bookingId : null, // Only set bookingId for multi-ticket bookings
-      userId: user.id,
-      eventId: data.eventId,
-      attendeeFirstName: attendee.firstName,
-      attendeeLastName: attendee.lastName && attendee.lastName.trim() ? attendee.lastName.trim() : null,
-      attendeeEmail: data.email, // Buyer's email for all tickets
-      attendeePhone: data.phone && data.phone.trim() ? data.phone.trim() : null,
-      attendeeRuc: data.ruc || null,
-      preferredLanguage: data.preferredLanguage || null,
-      status: 'pending',
-      qrCode,
-      checkinAt: null,
-      createdAt: now,
-    };
-    
-    await (db as any).insert(tickets).values(newTicket);
-    createdTickets.push(newTicket);
-    
-    // Create payment record for each ticket
-    const paymentId = generateId();
-    const newPayment = {
-      id: paymentId,
-      ticketId,
-      provider: data.paymentMethod,
-      amount: event.price,
-      currency: event.currency,
-      status: 'pending',
-      reference: null,
-      createdAt: now,
-      updatedAt: now,
-    };
-    
-    await (db as any).insert(payments).values(newPayment);
-    createdPayments.push(newPayment);
+
+  // Atomically re-check capacity and insert tickets/payments inside a transaction
+  // so concurrent bookings cannot oversell the same seats (TOCTOU race).
+  class BookingCapacityError extends Error {
+    constructor(public code: 'SOLD_OUT' | 'NOT_ENOUGH', public available?: number) {
+      super(code);
+    }
+  }
+
+  let createdTickets: any[] = [];
+  let createdPayments: any[] = [];
+
+  try {
+    if (isSqlite()) {
+      (db as any).transaction((tx: any) => {
+        const countRow = tx
+          .select({ count: sql<number>`count(*)` })
+          .from(tickets)
+          .where(
+            and(
+              eq((tickets as any).eventId, data.eventId),
+              sql`${(tickets as any).status} IN ('pending', 'confirmed', 'checked_in')`
+            )
+          )
+          .get();
+        const reserved = Number(countRow?.count || 0);
+        if (isEventSoldOut(event.capacity, reserved)) {
+          throw new BookingCapacityError('SOLD_OUT');
+        }
+        const seatsLeft = calculateAvailableSeats(event.capacity, reserved);
+        if (ticketCount > seatsLeft) {
+          throw new BookingCapacityError('NOT_ENOUGH', seatsLeft);
+        }
+
+        for (let i = 0; i < attendeesList.length; i++) {
+          const attendee = attendeesList[i];
+          const ticketId = generateId();
+          const qrCode = generateTicketCode();
+          const newTicket = {
+            id: ticketId,
+            bookingId: ticketCount > 1 ? bookingId : null,
+            userId: user.id,
+            eventId: data.eventId,
+            attendeeFirstName: attendee.firstName,
+            attendeeLastName: attendee.lastName && attendee.lastName.trim() ? attendee.lastName.trim() : null,
+            attendeeEmail: data.email,
+            attendeePhone: data.phone && data.phone.trim() ? data.phone.trim() : null,
+            attendeeRuc: data.ruc || null,
+            preferredLanguage: data.preferredLanguage || null,
+            status: 'pending',
+            qrCode,
+            checkinAt: null,
+            createdAt: now,
+          };
+          tx.insert(tickets).values(newTicket).run();
+          createdTickets.push(newTicket);
+
+          const paymentId = generateId();
+          const newPayment = {
+            id: paymentId,
+            ticketId,
+            provider: data.paymentMethod,
+            amount: event.price,
+            currency: event.currency,
+            status: 'pending',
+            reference: null,
+            createdAt: now,
+            updatedAt: now,
+          };
+          tx.insert(payments).values(newPayment).run();
+          createdPayments.push(newPayment);
+        }
+      });
+    } else {
+      await (db as any).transaction(async (tx: any) => {
+        const countRow = await dbGet<any>(
+          tx
+            .select({ count: sql<number>`count(*)` })
+            .from(tickets)
+            .where(
+              and(
+                eq((tickets as any).eventId, data.eventId),
+                sql`${(tickets as any).status} IN ('pending', 'confirmed', 'checked_in')`
+              )
+            )
+        );
+        const reserved = Number(countRow?.count || 0);
+        if (isEventSoldOut(event.capacity, reserved)) {
+          throw new BookingCapacityError('SOLD_OUT');
+        }
+        const seatsLeft = calculateAvailableSeats(event.capacity, reserved);
+        if (ticketCount > seatsLeft) {
+          throw new BookingCapacityError('NOT_ENOUGH', seatsLeft);
+        }
+
+        for (let i = 0; i < attendeesList.length; i++) {
+          const attendee = attendeesList[i];
+          const ticketId = generateId();
+          const qrCode = generateTicketCode();
+          const newTicket = {
+            id: ticketId,
+            bookingId: ticketCount > 1 ? bookingId : null,
+            userId: user.id,
+            eventId: data.eventId,
+            attendeeFirstName: attendee.firstName,
+            attendeeLastName: attendee.lastName && attendee.lastName.trim() ? attendee.lastName.trim() : null,
+            attendeeEmail: data.email,
+            attendeePhone: data.phone && data.phone.trim() ? data.phone.trim() : null,
+            attendeeRuc: data.ruc || null,
+            preferredLanguage: data.preferredLanguage || null,
+            status: 'pending',
+            qrCode,
+            checkinAt: null,
+            createdAt: now,
+          };
+          await tx.insert(tickets).values(newTicket);
+          createdTickets.push(newTicket);
+
+          const paymentId = generateId();
+          const newPayment = {
+            id: paymentId,
+            ticketId,
+            provider: data.paymentMethod,
+            amount: event.price,
+            currency: event.currency,
+            status: 'pending',
+            reference: null,
+            createdAt: now,
+            updatedAt: now,
+          };
+          await tx.insert(payments).values(newPayment);
+          createdPayments.push(newPayment);
+        }
+      });
+    }
+  } catch (err: any) {
+    if (err instanceof BookingCapacityError) {
+      if (err.code === 'SOLD_OUT') {
+        return c.json({ error: 'Event is sold out' }, 400);
+      }
+      return c.json({
+        error: `Not enough seats available. Only ${err.available} spot(s) remaining.`,
+      }, 400);
+    }
+    throw err;
   }
   
   const primaryTicket = createdTickets[0];
@@ -221,11 +360,26 @@ ticketsRouter.post('/', zValidator('json', createTicketSchema), async (c) => {
     });
   }
   
-  // If Lightning payment, create LNbits invoice
+  // If Lightning payment, create LNbits invoice (skip for free events — confirm immediately)
   let lnbitsInvoice = null;
   const totalPrice = event.price * ticketCount;
-  
-  if (data.paymentMethod === 'lightning' && totalPrice > 0) {
+
+  // Free events: no payment step required — confirm tickets immediately
+  if (totalPrice === 0) {
+    for (const t of createdTickets) {
+      await (db as any)
+        .update(tickets)
+        .set({ status: 'confirmed' })
+        .where(and(eq((tickets as any).id, t.id), eq((tickets as any).status, 'pending')));
+      await (db as any)
+        .update(payments)
+        .set({ status: 'paid', paidAt: now, updatedAt: now })
+        .where(and(eq((payments as any).ticketId, t.id), eq((payments as any).status, 'pending')));
+    }
+    emailService.sendBookingConfirmation(primaryTicket.id).catch(err => {
+      console.error('[Email] Failed to send free-booking confirmation:', err);
+    });
+  } else if (data.paymentMethod === 'lightning') {
     if (!isLNbitsConfigured()) {
       // Delete the tickets and payments we just created
       for (const payment of createdPayments) {
@@ -241,6 +395,11 @@ ticketsRouter.post('/', zValidator('json', createTicketSchema), async (c) => {
     
     try {
       const apiUrl = process.env.API_URL || 'http://localhost:3001';
+      // Include the webhook secret (if configured) so the callback can be authenticated
+      const webhookSecret = process.env.LNBITS_WEBHOOK_SECRET || '';
+      const webhookUrl = webhookSecret
+        ? `${apiUrl}/api/lnbits/webhook?token=${encodeURIComponent(webhookSecret)}`
+        : `${apiUrl}/api/lnbits/webhook`;
       
       // Pass the fiat currency directly to LNbits - it handles conversion automatically
       // For multi-ticket, use total price
@@ -248,7 +407,7 @@ ticketsRouter.post('/', zValidator('json', createTicketSchema), async (c) => {
         amount: totalPrice,
         unit: event.currency, // LNbits supports fiat currencies like USD, PYG, etc.
         memo: `Spanglish: ${event.title} - ${fullName}${ticketCount > 1 ? ` (${ticketCount} tickets)` : ''}`,
-        webhookUrl: `${apiUrl}/api/lnbits/webhook`,
+        webhookUrl,
         expiry: 900, // 15 minutes expiry for faster UX
         extra: {
           ticketId: primaryTicket.id,
@@ -610,6 +769,9 @@ ticketsRouter.get('/search', requireAuth(['admin', 'organizer', 'staff']), async
 });
 
 // Get ticket by ID
+// Capability-based access: the unguessable ticket UUID acts as the access token for
+// guest bookings (no account required). For anonymous callers we withhold attendee PII
+// (email/phone/RUC); the full record is only returned to the owner or admin/staff.
 ticketsRouter.get('/:id', async (c) => {
   const id = c.req.param('id');
   
@@ -639,15 +801,22 @@ ticketsRouter.get('/:id', async (c) => {
     );
     bookingTicketCount = bookingTickets.length || 1;
   }
+
+  // Determine whether the requester is the owner or an admin/staff member
+  const authUser: any = await getAuthUser(c);
+  const isPrivileged = !!authUser && (
+    ['admin', 'organizer', 'staff'].includes(authUser.role) || authUser.id === ticket.userId
+  );
+
+  const ticketPayload: any = { ...ticket, event, payment, bookingTicketCount };
+  if (!isPrivileged) {
+    // Strip attendee PII for anonymous capability-based access
+    delete ticketPayload.attendeeEmail;
+    delete ticketPayload.attendeePhone;
+    delete ticketPayload.attendeeRuc;
+  }
   
-  return c.json({
-    ticket: {
-      ...ticket,
-      event,
-      payment,
-      bookingTicketCount,
-    },
-  });
+  return c.json({ ticket: ticketPayload });
 });
 
 // Update ticket status (admin/organizer)
@@ -985,7 +1154,7 @@ ticketsRouter.post('/:id/mark-paid', requireAuth(['admin', 'organizer', 'staff']
 
 // User marks payment as sent (for manual payment methods: bank_transfer, tpago)
 // This sets status to "pending_approval" and notifies admin
-ticketsRouter.post('/:id/mark-payment-sent', async (c) => {
+ticketsRouter.post('/:id/mark-payment-sent', rateLimitMiddleware({ max: 10, windowMs: 10 * 60 * 1000, prefix: 'mark-payment-sent' }), async (c) => {
   const id = c.req.param('id');
   const body = await c.req.json().catch(() => ({}));
   const { payerName } = body;
@@ -1039,18 +1208,33 @@ ticketsRouter.post('/:id/mark-payment-sent', async (c) => {
   
   const now = getNow();
   
-  // Update payment status to pending_approval
-  await (db as any)
-    .update(payments)
-    .set({ 
-      status: 'pending_approval',
-      userMarkedPaidAt: now,
-      payerName: payerName?.trim() || null,
-      updatedAt: now,
-    })
-    .where(eq((payments as any).id, payment.id));
+  // Update payment status to pending_approval for this ticket and any siblings
+  // in a multi-ticket booking (mirrors the approve flow's bookingId fan-out).
+  let ticketsToMark: any[] = [ticket];
+  if (ticket.bookingId) {
+    ticketsToMark = await dbAll<any>(
+      (db as any).select().from(tickets).where(eq((tickets as any).bookingId, ticket.bookingId))
+    );
+  }
+
+  for (const t of ticketsToMark) {
+    await (db as any)
+      .update(payments)
+      .set({ 
+        status: 'pending_approval',
+        userMarkedPaidAt: now,
+        payerName: payerName?.trim() || null,
+        updatedAt: now,
+      })
+      .where(
+        and(
+          eq((payments as any).ticketId, (t as any).id),
+          eq((payments as any).status, 'pending')
+        )
+      );
+  }
   
-  // Get updated payment
+  // Get updated payment for the requested ticket
   const updatedPayment = await dbGet(
     (db as any)
       .select()
diff --git a/backend/src/routes/users.ts b/backend/src/routes/users.ts
index bc558b1..3773812 100644
--- a/backend/src/routes/users.ts
+++ b/backend/src/routes/users.ts
@@ -50,6 +50,29 @@ usersRouter.get('/', requireAuth(['admin']), async (c) => {
   return c.json({ users: result });
 });
 
+// Get user statistics (admin) — registered before /:id so "stats" is not parsed as a user id
+usersRouter.get('/stats/overview', requireAuth(['admin']), async (c) => {
+  const totalUsers = await dbGet<any>(
+    (db as any)
+      .select({ count: sql<number>`count(*)` })
+      .from(users)
+  );
+  
+  const adminCount = await dbGet<any>(
+    (db as any)
+      .select({ count: sql<number>`count(*)` })
+      .from(users)
+      .where(eq((users as any).role, 'admin'))
+  );
+  
+  return c.json({
+    stats: {
+      total: totalUsers?.count || 0,
+      admins: adminCount?.count || 0,
+    },
+  });
+});
+
 // Get user by ID (admin or self)
 usersRouter.get('/:id', requireAuth(['admin', 'organizer', 'staff', 'marketing', 'user']), async (c) => {
   const id = c.req.param('id');
@@ -286,27 +309,4 @@ usersRouter.delete('/:id', requireAuth(['admin']), async (c) => {
   }
 });
 
-// Get user statistics (admin)
-usersRouter.get('/stats/overview', requireAuth(['admin']), async (c) => {
-  const totalUsers = await dbGet<any>(
-    (db as any)
-      .select({ count: sql<number>`count(*)` })
-      .from(users)
-  );
-  
-  const adminCount = await dbGet<any>(
-    (db as any)
-      .select({ count: sql<number>`count(*)` })
-      .from(users)
-      .where(eq((users as any).role, 'admin'))
-  );
-  
-  return c.json({
-    stats: {
-      total: totalUsers?.count || 0,
-      admins: adminCount?.count || 0,
-    },
-  });
-});
-
 export default usersRouter;
diff --git a/frontend/next.config.js b/frontend/next.config.js
index 264227e..f34c070 100644
--- a/frontend/next.config.js
+++ b/frontend/next.config.js
@@ -1,28 +1,51 @@
 /** @type {import('next').NextConfig} */
+
+// Backend origin for API/upload proxying. Configurable per environment instead of
+// being hardcoded to localhost.
+const BACKEND_URL = process.env.BACKEND_URL || 'http://localhost:3001';
+
+// Extra image hosts can be allowed via a comma-separated env var (e.g. a CDN).
+const extraImageHosts = (process.env.NEXT_PUBLIC_IMAGE_HOSTS || '')
+  .split(',')
+  .map((h) => h.trim())
+  .filter(Boolean)
+  .map((hostname) => ({ protocol: 'https', hostname }));
+
+const securityHeaders = [
+  { key: 'X-Content-Type-Options', value: 'nosniff' },
+  { key: 'X-Frame-Options', value: 'SAMEORIGIN' },
+  { key: 'Referrer-Policy', value: 'strict-origin-when-cross-origin' },
+  { key: 'X-XSS-Protection', value: '0' },
+  { key: 'Permissions-Policy', value: 'camera=(self), microphone=(), geolocation=()' },
+];
+
 const nextConfig = {
   images: {
-    domains: ['localhost', 'images.unsplash.com'],
+    // Restrict remote image sources to a known allowlist instead of allowing any
+    // https host (which let the Next image optimizer be used as an open proxy).
     remotePatterns: [
-      {
-        protocol: 'https',
-        hostname: '**',
-      },
-      {
-        protocol: 'http',
-        hostname: 'localhost',
-        port: '3001',
-      },
+      { protocol: 'https', hostname: 'images.unsplash.com' },
+      { protocol: 'http', hostname: 'localhost', port: '3001' },
+      ...extraImageHosts,
     ],
   },
+  async headers() {
+    return [
+      {
+        source: '/:path*',
+        headers: securityHeaders,
+      },
+    ];
+  },
   async rewrites() {
     return [
       {
         source: '/api/:path*',
-        destination: 'http://localhost:3001/api/:path*',
+        destination: `${BACKEND_URL}/api/:path*`,
       },
       {
         source: '/uploads/:path*',
-        destination: 'http://localhost:3001/uploads/:path*',
+        destination: `${BACKEND_URL}/uploads/:path*`,
       },
     ];
   },
diff --git a/frontend/src/app/(public)/book/[eventId]/page.tsx b/frontend/src/app/(public)/book/[eventId]/page.tsx
index 8eeaf84..5d2d909 100644
--- a/frontend/src/app/(public)/book/[eventId]/page.tsx
+++ b/frontend/src/app/(public)/book/[eventId]/page.tsx
@@ -7,6 +7,7 @@ import { useLanguage } from '@/context/LanguageContext';
 import { useAuth } from '@/context/AuthContext';
 import { eventsApi, ticketsApi, paymentOptionsApi, Event, PaymentOptionsConfig } from '@/lib/api';
 import { formatPrice, formatDateLong, formatTime, getTpagoLink } from '@/lib/utils';
+import { isSafeExternalUrl } from '@/lib/safeRedirect';
 import Card from '@/components/ui/Card';
 import Button from '@/components/ui/Button';
 import Input from '@/components/ui/Input';
@@ -155,8 +156,12 @@ export default function BookingPage() {
             return;
           }
 
-          // Redirect to external booking if enabled
-          if (eventRes.event.externalBookingEnabled && eventRes.event.externalBookingUrl) {
+          // Redirect to external booking if enabled (only https:// targets are allowed)
+          if (
+            eventRes.event.externalBookingEnabled &&
+            eventRes.event.externalBookingUrl &&
+            isSafeExternalUrl(eventRes.event.externalBookingUrl)
+          ) {
             window.location.href = eventRes.event.externalBookingUrl;
             return;
           }
@@ -473,6 +478,16 @@ export default function BookingPage() {
           paymentMethod: formData.paymentMethod,
           ticketCount,
         });
+        // Fetch full payment credentials now that we hold a ticket capability token
+        try {
+          const { paymentOptions } = await paymentOptionsApi.getForEvent(
+            params.eventId as string,
+            primaryTicket.id
+          );
+          setPaymentConfig(paymentOptions);
+        } catch {
+          // Keep the flags-only config from initial load if the gated fetch fails
+        }
         setStep('manual_payment');
       } else {
         // Cash payment - go straight to success
diff --git a/frontend/src/app/(public)/booking/[ticketId]/page.tsx b/frontend/src/app/(public)/booking/[ticketId]/page.tsx
index 91f6116..5a371ed 100644
--- a/frontend/src/app/(public)/booking/[ticketId]/page.tsx
+++ b/frontend/src/app/(public)/booking/[ticketId]/page.tsx
@@ -69,7 +69,7 @@ export default function BookingPaymentPage() {
 
         // Get payment config for the event
         if (ticketData.eventId) {
-          const { paymentOptions } = await paymentOptionsApi.getForEvent(ticketData.eventId);
+          const { paymentOptions } = await paymentOptionsApi.getForEvent(ticketData.eventId, ticketData.id);
           setPaymentConfig(paymentOptions);
         }
 
diff --git a/frontend/src/app/(public)/login/page.tsx b/frontend/src/app/(public)/login/page.tsx
index 9ae5864..809c09d 100644
--- a/frontend/src/app/(public)/login/page.tsx
+++ b/frontend/src/app/(public)/login/page.tsx
@@ -10,6 +10,7 @@ import Button from '@/components/ui/Button';
 import Input from '@/components/ui/Input';
 import GoogleSignInButton from '@/components/GoogleSignInButton';
 import { authApi } from '@/lib/api';
+import { safeInternalPath } from '@/lib/safeRedirect';
 import toast from 'react-hot-toast';
 
 function LoginContent() {
@@ -25,8 +26,8 @@ function LoginContent() {
     password: '',
   });
 
-  // Check for redirect after login
-  const redirectTo = searchParams.get('redirect') || '/dashboard';
+  // Check for redirect after login (only same-origin relative paths are honoured)
+  const redirectTo = safeInternalPath(searchParams.get('redirect'), '/dashboard');
 
   const handleSubmit = async (e: React.FormEvent) => {
     e.preventDefault();
diff --git a/frontend/src/app/admin/emails/page.tsx b/frontend/src/app/admin/emails/page.tsx
index 2e2b754..66c97ed 100644
--- a/frontend/src/app/admin/emails/page.tsx
+++ b/frontend/src/app/admin/emails/page.tsx
@@ -1047,6 +1047,7 @@ export default function AdminEmailsPage() {
             <div className="flex-1 overflow-auto">
               <iframe
                 srcDoc={previewHtml}
+                sandbox=""
                 className="w-full h-full min-h-[500px]"
                 title="Email Preview"
               />
@@ -1100,6 +1101,7 @@ export default function AdminEmailsPage() {
               {selectedLog.bodyHtml ? (
                 <iframe
                   srcDoc={selectedLog.bodyHtml}
+                  sandbox=""
                   className="w-full h-full min-h-[400px]"
                   title="Email Content"
                 />
diff --git a/frontend/src/app/admin/events/[id]/page.tsx b/frontend/src/app/admin/events/[id]/page.tsx
index ae195e8..a412a8d 100644
--- a/frontend/src/app/admin/events/[id]/page.tsx
+++ b/frontend/src/app/admin/events/[id]/page.tsx
@@ -2217,7 +2217,7 @@ export default function AdminEventDetailPage() {
               <Button variant="outline" size="sm" onClick={() => setPreviewHtml(null)} className="min-h-[44px] md:min-h-0">Close</Button>
             </div>
             <div className="flex-1 overflow-auto">
-              <iframe srcDoc={previewHtml} className="w-full h-full min-h-[500px]" title="Email Preview" />
+              <iframe srcDoc={previewHtml} sandbox="" className="w-full h-full min-h-[500px]" title="Email Preview" />
             </div>
           </Card>
         </div>
diff --git a/frontend/src/app/api/revalidate/route.ts b/frontend/src/app/api/revalidate/route.ts
index 289d709..9476cd5 100644
--- a/frontend/src/app/api/revalidate/route.ts
+++ b/frontend/src/app/api/revalidate/route.ts
@@ -1,14 +1,27 @@
 import { revalidateTag } from 'next/cache';
 import { NextRequest, NextResponse } from 'next/server';
+import { timingSafeEqual } from 'crypto';
+
+// Constant-time string comparison to avoid leaking the secret via response timing.
+function secretsMatch(provided: unknown, expected: string): boolean {
+  if (typeof provided !== 'string' || provided.length === 0) return false;
+  const a = Buffer.from(provided);
+  const b = Buffer.from(expected);
+  if (a.length !== b.length) return false;
+  return timingSafeEqual(a, b);
+}
 
 export async function POST(request: NextRequest) {
   try {
     const body = await request.json();
     const { secret, tag } = body;
 
-    // Validate the revalidation secret
+    // Validate the revalidation secret. Reject if it is unset or left at an insecure default.
     const revalidateSecret = process.env.REVALIDATE_SECRET;
-    if (!revalidateSecret || secret !== revalidateSecret) {
+    if (!revalidateSecret || revalidateSecret === 'change-me' || revalidateSecret.length < 16) {
+      return NextResponse.json({ error: 'Revalidation is not configured' }, { status: 503 });
+    }
+    if (!secretsMatch(secret, revalidateSecret)) {
       return NextResponse.json({ error: 'Invalid secret' }, { status: 401 });
     }
 
diff --git a/frontend/src/components/GoogleSignInButton.tsx b/frontend/src/components/GoogleSignInButton.tsx
index afda3a7..a2f0383 100644
--- a/frontend/src/components/GoogleSignInButton.tsx
+++ b/frontend/src/components/GoogleSignInButton.tsx
@@ -3,6 +3,7 @@
 import { useEffect, useRef, useState, useCallback } from 'react';
 import { useAuth } from '@/context/AuthContext';
 import { useLanguage } from '@/context/LanguageContext';
+import { safeInternalPath } from '@/lib/safeRedirect';
 import toast from 'react-hot-toast';
 
 declare global {
@@ -82,10 +83,9 @@ export default function GoogleSignInButton({
         toast.success(locale === 'es' ? 'Bienvenido!' : 'Welcome!');
         onSuccess?.();
         
-        // Use window.location for navigation to ensure clean state
-        if (redirectTo) {
-          window.location.href = redirectTo;
-        }
+        // Use window.location for navigation to ensure clean state.
+        // Constrain to a same-origin path to avoid open redirects.
+        window.location.href = safeInternalPath(redirectTo, '/dashboard');
       } catch (error: unknown) {
         const errorMessage = error instanceof Error ? error.message : 'Google login failed';
         const displayError = locale === 'es' ? 'Error al iniciar sesion con Google' : errorMessage;
diff --git a/frontend/src/components/layout/LegalPageLayout.tsx b/frontend/src/components/layout/LegalPageLayout.tsx
index 5e05400..fc76d97 100644
--- a/frontend/src/components/layout/LegalPageLayout.tsx
+++ b/frontend/src/components/layout/LegalPageLayout.tsx
@@ -21,6 +21,17 @@ function extractLastUpdated(contentMarkdown: string, updatedAt?: string): string
   return match ? match[1].trim() : updatedAt;
 }
 
+// Only permit safe link schemes. Anything else (javascript:, data:, etc.) is dropped
+// so a malicious markdown link can't execute script when clicked.
+function sanitizeHref(href?: string): string | undefined {
+  if (!href) return undefined;
+  const trimmed = href.trim();
+  // Allow relative/anchor/protocol-relative-safe links
+  if (trimmed.startsWith('/') || trimmed.startsWith('#')) return trimmed;
+  if (/^(https?:|mailto:|tel:)/i.test(trimmed)) return trimmed;
+  return undefined;
+}
+
 export default function LegalPageLayout({
   slug,
   initialLocale,
@@ -141,17 +152,20 @@ export default function LegalPageLayout({
                   {children}
                 </li>
               ),
-              // Style links
-              a: ({ href, children }) => (
-                <a 
-                  href={href}
-                  className="text-primary-dark underline hover:text-primary-yellow transition-colors"
-                  target={href?.startsWith('http') ? '_blank' : undefined}
-                  rel={href?.startsWith('http') ? 'noopener noreferrer' : undefined}
-                >
-                  {children}
-                </a>
-              ),
+              // Style links (with scheme allowlist to block javascript:/data: URLs)
+              a: ({ href, children }) => {
+                const safeHref = sanitizeHref(href);
+                return (
+                  <a 
+                    href={safeHref}
+                    className="text-primary-dark underline hover:text-primary-yellow transition-colors"
+                    target={safeHref?.startsWith('http') ? '_blank' : undefined}
+                    rel={safeHref?.startsWith('http') ? 'noopener noreferrer' : undefined}
+                  >
+                    {children}
+                  </a>
+                );
+              },
               // Style horizontal rules
               hr: () => (
                 <hr className="my-8 border-gray-200" />
diff --git a/frontend/src/components/ui/RichTextEditor.tsx b/frontend/src/components/ui/RichTextEditor.tsx
index 5d07214..214a8e8 100644
--- a/frontend/src/components/ui/RichTextEditor.tsx
+++ b/frontend/src/components/ui/RichTextEditor.tsx
@@ -14,11 +14,18 @@ interface RichTextEditorProps {
   editable?: boolean;
 }
 
+// Escape HTML-significant characters so any raw HTML embedded in the markdown source
+// is neutralised before we layer our own generated tags on top (defense-in-depth;
+// the public renderer escapes too, and TipTap sanitizes via its schema).
+function escapeRawHtml(s: string): string {
+  return s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
+}
+
 // Convert markdown to HTML for TipTap
 function markdownToHtml(markdown: string): string {
   if (!markdown) return '<p></p>';
   
-  let html = markdown;
+  let html = escapeRawHtml(markdown);
   
   // Convert horizontal rules first (before other processing)
   html = html.replace(/^---+$/gm, '<hr>');
diff --git a/frontend/src/context/AuthContext.tsx b/frontend/src/context/AuthContext.tsx
index 132dc67..3769260 100644
--- a/frontend/src/context/AuthContext.tsx
+++ b/frontend/src/context/AuthContext.tsx
@@ -44,6 +44,17 @@ const AuthContext = createContext<AuthContextType | undefined>(undefined);
 
 const TOKEN_KEY = 'spanglish-token';
 const USER_KEY = 'spanglish-user';
+const AUTH_COOKIE = 'spanglish-auth';
+
+function setAuthCookie() {
+  if (typeof document === 'undefined') return;
+  document.cookie = `${AUTH_COOKIE}=1; path=/; max-age=${60 * 60 * 24}; SameSite=Lax`;
+}
+
+function clearAuthCookie() {
+  if (typeof document === 'undefined') return;
+  document.cookie = `${AUTH_COOKIE}=; path=/; max-age=0; SameSite=Lax`;
+}
 
 export function AuthProvider({ children }: { children: ReactNode }) {
   const [user, setUser] = useState<User | null>(null);
@@ -66,12 +77,14 @@ export function AuthProvider({ children }: { children: ReactNode }) {
         const data = await res.json();
         setUser(data.user);
         localStorage.setItem(USER_KEY, JSON.stringify(data.user));
+        setAuthCookie();
       } else if (res.status === 401) {
         // Token is invalid, clear auth state
         setToken(null);
         setUser(null);
         localStorage.removeItem(TOKEN_KEY);
         localStorage.removeItem(USER_KEY);
+        clearAuthCookie();
       }
     } catch (error) {
       // Network error, keep using cached data
@@ -85,10 +98,24 @@ export function AuthProvider({ children }: { children: ReactNode }) {
     const savedUser = localStorage.getItem(USER_KEY);
     
     if (savedToken && savedUser) {
-      setToken(savedToken);
-      setUser(JSON.parse(savedUser));
-      // Refresh user data from server to get latest role/permissions
-      refreshUser().finally(() => setIsLoading(false));
+      // Guard against corrupt/tampered localStorage so the whole app doesn't crash.
+      let parsedUser: User | null = null;
+      try {
+        parsedUser = JSON.parse(savedUser);
+      } catch {
+        parsedUser = null;
+      }
+
+      if (parsedUser) {
+        setToken(savedToken);
+        setUser(parsedUser);
+        // Refresh user data from server to get latest role/permissions (source of truth)
+        refreshUser().finally(() => setIsLoading(false));
+      } else {
+        localStorage.removeItem(TOKEN_KEY);
+        localStorage.removeItem(USER_KEY);
+        setIsLoading(false);
+      }
     } else {
       setIsLoading(false);
     }
@@ -99,6 +126,7 @@ export function AuthProvider({ children }: { children: ReactNode }) {
     setUser(data.user);
     localStorage.setItem(TOKEN_KEY, data.token);
     localStorage.setItem(USER_KEY, JSON.stringify(data.user));
+    setAuthCookie();
   }, []);
 
   const login = async (email: string, password: string) => {
@@ -166,10 +194,21 @@ export function AuthProvider({ children }: { children: ReactNode }) {
   };
 
   const logout = useCallback(() => {
+    // Best-effort server-side invalidation (bumps token version so the JWT can't be reused).
+    const currentToken = localStorage.getItem(TOKEN_KEY);
+    if (currentToken) {
+      fetch(`${API_BASE}/api/auth/logout`, {
+        method: 'POST',
+        headers: { 'Authorization': `Bearer ${currentToken}` },
+      }).catch(() => {
+        // Ignore network errors; local state is cleared regardless.
+      });
+    }
     setToken(null);
     setUser(null);
     localStorage.removeItem(TOKEN_KEY);
     localStorage.removeItem(USER_KEY);
+    clearAuthCookie();
   }, []);
 
   const updateUser = useCallback((updatedUser: User) => {
diff --git a/frontend/src/lib/api.ts b/frontend/src/lib/api.ts
index 3e9149c..eda79f9 100644
--- a/frontend/src/lib/api.ts
+++ b/frontend/src/lib/api.ts
@@ -314,10 +314,11 @@ export const paymentOptionsApi = {
       body: JSON.stringify(data),
     }),
   
-  // Event-specific options (merged with global)
-  getForEvent: (eventId: string) =>
+  // Event-specific options (merged with global). Pass ticketId after booking to
+  // retrieve bank/TPago credentials gated behind the booking capability token.
+  getForEvent: (eventId: string, ticketId?: string) =>
     fetchApi<{ paymentOptions: PaymentOptionsConfig; hasOverrides: boolean }>(
-      `/api/payment-options/event/${eventId}`
+      `/api/payment-options/event/${eventId}${ticketId ? `?ticketId=${encodeURIComponent(ticketId)}` : ''}`
     ),
   
   // Event overrides (admin only)
diff --git a/frontend/src/lib/safeRedirect.ts b/frontend/src/lib/safeRedirect.ts
new file mode 100644
index 0000000..24f34e6
--- /dev/null
+++ b/frontend/src/lib/safeRedirect.ts
@@ -0,0 +1,31 @@
+/**
+ * Returns a safe internal redirect path, or the provided fallback.
+ *
+ * Only same-origin relative paths are allowed (must start with a single "/" and not
+ * "//", which the browser treats as protocol-relative -> external). This prevents
+ * open-redirect attacks via a `?redirect=` parameter.
+ */
+export function safeInternalPath(value: string | null | undefined, fallback: string = '/'): string {
+  if (!value) return fallback;
+  // Must be a relative path rooted at "/", but not "//" or "/\" (protocol-relative).
+  if (!value.startsWith('/')) return fallback;
+  if (value.startsWith('//') || value.startsWith('/\\')) return fallback;
+  // Reject attempts to smuggle a scheme or control characters.
+  if (/[\x00-\x1f]/.test(value) || value.includes('\\')) return fallback;
+  return value;
+}
+
+/**
+ * Returns true if a URL is safe to use as an external navigation target:
+ * an absolute https:// URL, or a same-origin relative path.
+ */
+export function isSafeExternalUrl(value: string | null | undefined): boolean {
+  if (!value) return false;
+  if (value.startsWith('/') && !value.startsWith('//') && !value.startsWith('/\\')) return true;
+  try {
+    const url = new URL(value);
+    return url.protocol === 'https:';
+  } catch {
+    return false;
+  }
+}
diff --git a/frontend/src/middleware.ts b/frontend/src/middleware.ts
new file mode 100644
index 0000000..5ada6b7
--- /dev/null
+++ b/frontend/src/middleware.ts
@@ -0,0 +1,27 @@
+import { NextRequest, NextResponse } from 'next/server';
+
+/**
+ * Defense-in-depth guard for authenticated areas.
+ *
+ * Auth tokens live in localStorage (not readable here), so we rely on a lightweight
+ * `spanglish-auth` cookie set alongside login. The API remains the authoritative gate;
+ * this only keeps unauthenticated visitors from loading the admin/dashboard JS shell.
+ */
+export function middleware(request: NextRequest) {
+  const { pathname } = request.nextUrl;
+
+  if (pathname.startsWith('/admin') || pathname.startsWith('/dashboard')) {
+    const hasAuthCookie = request.cookies.get('spanglish-auth')?.value === '1';
+    if (!hasAuthCookie) {
+      const loginUrl = new URL('/login', request.url);
+      loginUrl.searchParams.set('redirect', pathname);
+      return NextResponse.redirect(loginUrl);
+    }
+  }
+
+  return NextResponse.next();
+}
+
+export const config = {
+  matcher: ['/admin/:path*', '/dashboard/:path*'],
+};