diff --git a/AI/mcp-server/package.json b/AI/mcp-server/package.json
index f305309..a8a15a9 100644
--- a/AI/mcp-server/package.json
+++ b/AI/mcp-server/package.json
@@ -12,6 +12,7 @@
     "@azure/msal-node": "^5.4.1",
     "@modelcontextprotocol/sdk": "^1.29.0",
     "express": "^5.2.1",
+    "express-rate-limit": "^8.6.0",
     "zod": "^4.4.3"
   },
   "engines": {
diff --git a/AI/mcp-server/src/server.ts b/AI/mcp-server/src/server.ts
index 9b320c4..a7c3088 100644
--- a/AI/mcp-server/src/server.ts
+++ b/AI/mcp-server/src/server.ts
@@ -3,6 +3,7 @@ import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/
 import { SSEServerTransport } from '@modelcontextprotocol/sdk/server/sse.js';
 import express, { type Request, type Response, type NextFunction } from 'express';
 import { randomUUID } from 'node:crypto';
+import rateLimit from 'express-rate-limit';
 import type { GraphClient } from './graph.js';
 import type { AppConfig } from './config.js';
 import { registerContainerTools } from './tools/containers.js';
@@ -80,6 +81,14 @@ export function buildApp(graph: GraphClient, config: AppConfig): express.Applica
     next();
   }
 
+  // ── Rate limiting ─────────────────────────────────────────────────────────────
+  const messagesLimiter = rateLimit({
+    windowMs: 15 * 60 * 1000, // 15 minutes
+    max: 100, // limit each IP to 100 requests per windowMs
+    standardHeaders: true,
+    legacyHeaders: false,
+  });
+
   // ── Health ────────────────────────────────────────────────────────────────────
   app.get('/health', (_req, res) => {
     res.json({ status: 'ok', service: 'spe-mcp-server', version: '1.0.0' });
@@ -251,7 +260,7 @@ export function buildApp(graph: GraphClient, config: AppConfig): express.Applica
     }
   });
 
-  app.post('/messages', requireBearerToken, async (req: Request, res: Response) => {
+  app.post('/messages', messagesLimiter, requireBearerToken, async (req: Request, res: Response) => {
     const sessionId = req.query['sessionId'] as string | undefined;
     if (!sessionId) { res.status(400).json({ error: 'Missing sessionId' }); return; }
     const transport = sseTransports.get(sessionId);
diff --git a/AI/ocr/server/index.ts b/AI/ocr/server/index.ts
index b13df75..906df47 100644
--- a/AI/ocr/server/index.ts
+++ b/AI/ocr/server/index.ts
@@ -5,13 +5,22 @@ import { onReceiptAdded } from "./onReceiptAdded";
 
 const app = express();
 
+// Allowed origins: configure via ALLOWED_ORIGINS env var (comma-separated list).
+// Defaults to common local development origins.
+const allowedOrigins = new Set(
+  (process.env.ALLOWED_ORIGINS || 'http://localhost:3000,http://localhost:3001,https://localhost:3000,https://localhost:3001').split(',').map(o => o.trim()).filter(Boolean)
+);
+
 app.use(express.json());
 app.use(express.urlencoded({ extended: true }));
 
 app.use((req: Request, res: Response, next: NextFunction) => {
-  res.header('Access-Control-Allow-Origin', req.header('origin'));
-  res.header('Access-Control-Allow-Headers', req.header('Access-Control-Request-Headers'));
-  res.header('Access-Control-Allow-Credentials', 'true');
+  const origin = req.header('origin');
+  if (origin && allowedOrigins.has(origin)) {
+    res.header('Access-Control-Allow-Origin', origin);
+    res.header('Access-Control-Allow-Headers', req.header('Access-Control-Request-Headers'));
+    res.header('Access-Control-Allow-Credentials', 'true');
+  }
 
   if (req.method === 'OPTIONS') {
     return res.sendStatus(204);
diff --git a/Custom Apps/boilerplate-aspnet-webservice/Services/MSGraphService.cs b/Custom Apps/boilerplate-aspnet-webservice/Services/MSGraphService.cs
index 32e2307..ee7a5d5 100644
--- a/Custom Apps/boilerplate-aspnet-webservice/Services/MSGraphService.cs	
+++ b/Custom Apps/boilerplate-aspnet-webservice/Services/MSGraphService.cs	
@@ -163,7 +163,7 @@ public async Task<IEnumerable<ContainerPermissionModel>> GetContainerPermissions
         public async Task<ContainerPermissionModel> UpdateContainerPermission(string accessToken, string containerId, string permissionId, string role)
         {
             HttpClient client = GetHttpClient(accessToken, "application/json");
-            var json = $@"{{ ""roles"":[""{role}""]}}";
+            var json = JsonConvert.SerializeObject(new { roles = new[] { role } });
             HttpContent content = new StringContent(json, Encoding.UTF8, "application/json");
             var response = await client.PatchAsync($"{GraphContainersEndpoint}/{containerId}/permissions/{permissionId}", content);
 
diff --git a/Custom Apps/boilerplate-react-azurefunction/packages/azure-functions/web.config b/Custom Apps/boilerplate-react-azurefunction/packages/azure-functions/web.config
index 3c21bfc..2603003 100644
--- a/Custom Apps/boilerplate-react-azurefunction/packages/azure-functions/web.config	
+++ b/Custom Apps/boilerplate-react-azurefunction/packages/azure-functions/web.config	
@@ -1,6 +1,11 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <configuration>
     <system.webServer>
+        <httpProtocol>
+            <customHeaders>
+                <add name="X-Frame-Options" value="DENY" />
+            </customHeaders>
+        </httpProtocol>
         <rewrite>
             <rules>
                 <rule name = "Site Unavailable" stopProcessing = "true">
diff --git a/Custom Apps/webhook/src/server.js b/Custom Apps/webhook/src/server.js
index ead69e4..273d82f 100644
--- a/Custom Apps/webhook/src/server.js	
+++ b/Custom Apps/webhook/src/server.js	
@@ -31,6 +31,13 @@ app.post('/webhook', async (req, res) => {
     const resource = notification.resource; // e.g., drives/{drive-id}/items/{item-id}
 
     if (graphToken) {
+      // Validate the resource path to prevent path traversal or unexpected endpoints.
+      // Only allow alphanumeric characters, hyphens, underscores, and forward slashes.
+      const safeResourcePattern = /^[A-Za-z0-9_\-/]+$/;
+      if (!resource || !safeResourcePattern.test(resource)) {
+        console.warn('⚠️ Skipping metadata fetch — invalid resource path:', resource);
+        continue;
+      }
       try {
         const response = await axios.get(`https://graph.microsoft.com/v1.0/${resource}`, {
           headers: {