diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ca9f1c9..64bf093 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,6 +6,9 @@ on:
   pull_request:
     branches: [main]
 
+permissions:
+  contents: read
+
 jobs:
   test:
     name: Tests (Node.js ${{ matrix.node-version }})
diff --git a/CHANGELOG.md b/CHANGELOG.md
index da3a1ed..ebdfcb9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.5.2] - 2026-04-01
+
+### Security
+- Add rate limiting to SPA fallback route to prevent file system hammering via unauthenticated wildcard requests
+- Add CSRF protection to auth routes that change state (logout, create user, change password, delete user) — previously bypassed global CSRF middleware due to router registration order
+- Fix incomplete vCard escaping in contacts export — backslash characters are now escaped first before other special characters (`,`, `;`, newline), preventing injection via contact fields
+- Restrict CI workflow GITHUB_TOKEN to `contents: read` (principle of least privilege)
+
 ## [0.5.1] - 2026-04-01
 
 ### Fixed
diff --git a/package.json b/package.json
index bc19208..f551378 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "oikos",
-  "version": "0.5.1",
+  "version": "0.5.2",
   "description": "Selbstgehosteter Familienplaner — Kalender, Aufgaben, Einkauf, Essensplan, Budget und mehr. Privat, offen, ohne Abo.",
   "main": "server/index.js",
   "engines": {
diff --git a/server/auth.js b/server/auth.js
index 21b1090..64e5167 100644
--- a/server/auth.js
+++ b/server/auth.js
@@ -13,7 +13,7 @@ const session = require('express-session');
 const rateLimit = require('express-rate-limit');
 const db = require('./db');
 
-const { generateToken } = require('./middleware/csrf');
+const { generateToken, csrfMiddleware } = require('./middleware/csrf');
 const router = express.Router();
 
 // --------------------------------------------------------
@@ -218,7 +218,7 @@ router.post('/login', loginLimiter, async (req, res) => {
  * POST /api/v1/auth/logout
  * Response: { ok: true }
  */
-router.post('/logout', requireAuth, (req, res) => {
+router.post('/logout', requireAuth, csrfMiddleware, (req, res) => {
   req.session.destroy((err) => {
     if (err) {
       console.error('[Auth] Logout-Fehler:', err);
@@ -274,7 +274,7 @@ router.get('/users', requireAuth, requireAdmin, (req, res) => {
  * Body: { username, display_name, password, avatar_color?, role? }
  * Response: { user: { id, username, display_name, avatar_color, role } }
  */
-router.post('/users', requireAuth, requireAdmin, async (req, res) => {
+router.post('/users', requireAuth, requireAdmin, csrfMiddleware, async (req, res) => {
   try {
     const { username, display_name, password, avatar_color = '#007AFF', role = 'member' } = req.body;
 
@@ -313,7 +313,7 @@ router.post('/users', requireAuth, requireAdmin, async (req, res) => {
  * Body: { current_password: string, new_password: string }
  * Response: { ok: true }
  */
-router.patch('/me/password', requireAuth, async (req, res) => {
+router.patch('/me/password', requireAuth, csrfMiddleware, async (req, res) => {
   try {
     const { current_password, new_password } = req.body;
 
@@ -345,7 +345,7 @@ router.patch('/me/password', requireAuth, async (req, res) => {
  * Admin only. Löscht ein Familienmitglied.
  * Response: { ok: true }
  */
-router.delete('/users/:id', requireAuth, requireAdmin, (req, res) => {
+router.delete('/users/:id', requireAuth, requireAdmin, csrfMiddleware, (req, res) => {
   try {
     const userId = parseInt(req.params.id, 10);
 
diff --git a/server/index.js b/server/index.js
index 86ca38f..72e96cb 100644
--- a/server/index.js
+++ b/server/index.js
@@ -163,10 +163,21 @@ app.get('/health', (req, res) => {
   res.json({ status: 'ok', timestamp: new Date().toISOString() });
 });
 
+// --------------------------------------------------------
+// Rate-Limiter für SPA-Fallback (verhindert Dateisystem-Hammering)
+// --------------------------------------------------------
+const spaLimiter = rateLimit({
+  windowMs: 60_000,
+  max: 200,
+  standardHeaders: true,
+  legacyHeaders: false,
+  message: { error: 'Zu viele Anfragen. Bitte warte kurz.', code: 429 },
+});
+
 // --------------------------------------------------------
 // SPA Fallback: Alle nicht-API-Routen → index.html
 // --------------------------------------------------------
-app.get('*', (req, res) => {
+app.get('*', spaLimiter, (req, res) => {
   if (req.path.startsWith('/api/')) {
     return res.status(404).json({ error: 'Nicht gefunden.', code: 404 });
   }
diff --git a/server/routes/contacts.js b/server/routes/contacts.js
index a18f294..ab330a8 100644
--- a/server/routes/contacts.js
+++ b/server/routes/contacts.js
@@ -171,7 +171,7 @@ router.get('/:id/vcard', (req, res) => {
     const contact = db.get().prepare('SELECT * FROM contacts WHERE id = ?').get(id);
     if (!contact) return res.status(404).json({ error: 'Kontakt nicht gefunden', code: 404 });
 
-    const esc = (v) => String(v || '').replace(/\n/g, '\\n').replace(/,/g, '\\,').replace(/;/g, '\\;');
+    const esc = (v) => String(v || '').replace(/\\/g, '\\\\').replace(/\n/g, '\\n').replace(/,/g, '\\,').replace(/;/g, '\\;');
 
     const lines = [
       'BEGIN:VCARD',