Fix XSS vulnerability by sanitizing HTML in blog posts

Added DOMPurify library to sanitize HTML content before rendering with
dangerouslySetInnerHTML. This prevents Cross-Site Scripting (XSS) attacks
where malicious scripts could be injected through blog post content.

Changes:
- Installed dompurify and @types/dompurify
- Added HTML sanitization in BlogPost.tsx (client/pages/BlogPost.tsx:139)
- Added HTML sanitization in AdminBlogEditor.tsx preview (client/components/admin/AdminBlogEditor.tsx:273)

Security impact: HIGH - Previously, unsanitized HTML from the API could
execute arbitrary JavaScript, potentially stealing user credentials or
performing unauthorized actions.

client/components/admin/AdminBlogEditor.tsx

@@ -1,4 +1,5 @@
 import { useState } from "react";
+import DOMPurify from "dompurify";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Textarea } from "@/components/ui/textarea";
@@ -269,7 +270,7 @@ const BlogEditor = ({ onPublish, initialData }: BlogEditorProps) => {
             {excerpt && (
               <p className="text-muted-foreground italic">{excerpt}</p>
             )}
-            <div dangerouslySetInnerHTML={{ __html: html }} />
+            <div dangerouslySetInnerHTML={{ __html: DOMPurify.sanitize(html) }} />
           </CardContent>
         </Card>
       )}

client/pages/BlogPost.tsx

@@ -1,5 +1,6 @@
 import { useEffect, useState } from "react";
 import { useParams, Link } from "react-router-dom";
+import DOMPurify from "dompurify";
 import Layout from "@/components/Layout";
 import SEO from "@/components/SEO";
 import {
@@ -135,7 +136,7 @@ export default function BlogPost() {
               </CardHeader>
               <CardContent className="prose max-w-none mt-6">
                 {post.body ? (
-                  <div dangerouslySetInnerHTML={{ __html: post.body }} />
+                  <div dangerouslySetInnerHTML={{ __html: DOMPurify.sanitize(post.body) }} />
                 ) : (
                   <p>{post.excerpt}</p>
                 )}

package-lock.json

@@ -15,6 +15,7 @@
         "@vercel/analytics": "^1.5.0",
         "adm-zip": "^0.5.16",
         "chokidar": "^3.6.0",
+        "dompurify": "^3.3.1",
         "dotenv": "^17.2.0",
         "ethers": "^6.13.0",
         "express": "^4.18.2",
@@ -59,6 +60,7 @@
         "@tailwindcss/typography": "^0.5.15",
         "@tanstack/react-query": "^5.56.2",
         "@types/cors": "^2.8.17",
+        "@types/dompurify": "^3.0.5",
         "@types/express": "^4.17.21",
         "@types/node": "^22.5.5",
         "@types/nodemailer": "^7.0.3",
@@ -6881,6 +6883,16 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/@types/dompurify": {
+      "version": "3.0.5",
+      "resolved": "https://registry.npmjs.org/@types/dompurify/-/dompurify-3.0.5.tgz",
+      "integrity": "sha512-1Wg0g3BtQF7sSb27fJQAKck1HECM6zV1EB66j8JH9i3LCjYabJa0FSdiSgsD5K/RbrsR0SiraKacLB+T8ZVYAg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/trusted-types": "*"
+      }
+    },
     "node_modules/@types/draco3d": {
       "version": "1.4.10",
       "resolved": "https://registry.npmjs.org/@types/draco3d/-/draco3d-1.4.10.tgz",
@@ -7167,6 +7179,13 @@
         "meshoptimizer": "~0.18.1"
       }
     },
+    "node_modules/@types/trusted-types": {
+      "version": "2.0.7",
+      "resolved": "https://registry.npmjs.org/@types/trusted-types/-/trusted-types-2.0.7.tgz",
+      "integrity": "sha512-ScaPdn1dQczgbl0QFTeTOmVHFULt394XJgOQNoyVhZ6r2vLnMLJfBPd53SB52T/3G36VI1/g2MZaX0cwDuXsfw==",
+      "devOptional": true,
+      "license": "MIT"
+    },
     "node_modules/@types/uuid": {
       "version": "10.0.0",
       "resolved": "https://registry.npmjs.org/@types/uuid/-/uuid-10.0.0.tgz",
@@ -9853,6 +9872,15 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/dompurify": {
+      "version": "3.3.1",
+      "resolved": "https://registry.npmjs.org/dompurify/-/dompurify-3.3.1.tgz",
+      "integrity": "sha512-qkdCKzLNtrgPFP1Vo+98FRzJnBRGe4ffyCea9IwHB1fyxPOeNTHpLKYGd4Uk9xvNoH0ZoOjwZxNptyMwqrId1Q==",
+      "license": "(MPL-2.0 OR Apache-2.0)",
+      "optionalDependencies": {
+        "@types/trusted-types": "^2.0.7"
+      }
+    },
     "node_modules/dotenv": {
       "version": "17.2.3",
       "resolved": "https://registry.npmjs.org/dotenv/-/dotenv-17.2.3.tgz",

package.json

@@ -39,6 +39,7 @@
     "@vercel/analytics": "^1.5.0",
     "adm-zip": "^0.5.16",
     "chokidar": "^3.6.0",
+    "dompurify": "^3.3.1",
     "dotenv": "^17.2.0",
     "ethers": "^6.13.0",
     "express": "^4.18.2",
@@ -83,6 +84,7 @@
     "@tailwindcss/typography": "^0.5.15",
     "@tanstack/react-query": "^5.56.2",
     "@types/cors": "^2.8.17",
+    "@types/dompurify": "^3.0.5",
     "@types/express": "^4.17.21",
     "@types/node": "^22.5.5",
     "@types/nodemailer": "^7.0.3",