diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5e7ecf6..267019a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,6 +6,10 @@ on:
   pull_request:
     branches: [main, master]
 
+# Restrict permissions to minimum required (security best practice)
+permissions:
+  contents: read
+
 jobs:
   test:
     runs-on: ubuntu-latest
diff --git a/scripts/benchmark.js b/scripts/benchmark.js
index 798d52a..1a674a9 100755
--- a/scripts/benchmark.js
+++ b/scripts/benchmark.js
@@ -7,10 +7,21 @@
 
 import { UrbanKnowledgeMapper } from '../src/mapper.js';
 import { PerformanceMonitor, benchmark } from '../src/performance.js';
-import { randomUUID } from 'crypto';
+import { randomUUID, randomBytes } from 'crypto';
 
 const DATASET_SIZES = [10, 50, 100, 500, 1000];
 
+/**
+ * Generate a cryptographically secure random float between 0 and 1
+ * @returns {number} Random float in range [0, 1)
+ */
+function secureRandomFloat() {
+  // Use 4 bytes to create a 32-bit unsigned integer, then normalize to [0, 1)
+  const bytes = randomBytes(4);
+  const uint32 = bytes.readUInt32BE(0);
+  return uint32 / 0x100000000;
+}
+
 async function generateTestData(count) {
   const mapper = new UrbanKnowledgeMapper('/tmp/benchmark-ubicity');
   await mapper.initialize();
@@ -26,8 +37,8 @@ async function generateTestData(count) {
         location: {
           name: locations[i % locations.length],
           coordinates: {
-            latitude: 37.7749 + (Math.random() - 0.5) * 0.1,
-            longitude: -122.4194 + (Math.random() - 0.5) * 0.1,
+            latitude: 37.7749 + (secureRandomFloat() - 0.5) * 0.1,
+            longitude: -122.4194 + (secureRandomFloat() - 0.5) * 0.1,
           },
         },
       },
diff --git a/src/privacy.js b/src/privacy.js
index dd4bc35..6ade38d 100644
--- a/src/privacy.js
+++ b/src/privacy.js
@@ -207,11 +207,16 @@ function hashString(str) {
  * @returns {string} Sanitized text
  */
 function sanitizeText(text) {
-  let sanitized = text;
-
-  // Email addresses
+  // Limit input length to prevent ReDoS attacks
+  const MAX_TEXT_LENGTH = 10000;
+  let sanitized = text.length > MAX_TEXT_LENGTH
+    ? text.slice(0, MAX_TEXT_LENGTH)
+    : text;
+
+  // Email addresses - use possessive-like matching to prevent backtracking
+  // Pattern: local part (alphanumeric, limited special chars) @ domain
   sanitized = sanitized.replace(
-    /[\w.-]+@[\w.-]+\.\w+/g,
+    /[a-zA-Z0-9](?:[a-zA-Z0-9._-]{0,62}[a-zA-Z0-9])?@[a-zA-Z0-9](?:[a-zA-Z0-9.-]{0,252}[a-zA-Z0-9])?\.[a-zA-Z]{2,63}/g,
     '[email]'
   );
 
@@ -221,9 +226,9 @@ function sanitizeText(text) {
     '[phone]'
   );
 
-  // URLs
+  // URLs - use non-greedy matching with explicit character class
   sanitized = sanitized.replace(
-    /https?:\/\/[^\s]+/g,
+    /https?:\/\/[^\s]{1,2000}/g,
     '[url]'
   );