CVE-2025-63639
📋 TL;DR
CVE-2025-63639 is a stored cross-site scripting (XSS) vulnerability in Sourcecodester FAQ Bot with AI Assistant v1.0 that allows attackers to inject malicious scripts into chat messages. When other users view the conversation, the scripts execute in their browsers, potentially stealing session cookies, redirecting to malicious sites, or performing actions on their behalf. This affects all users of the vulnerable application version.
💻 Affected Systems
- Sourcecodester FAQ Bot with AI Assistant
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator session cookies, gain full administrative access to the application, deface the site, or redirect users to phishing/malware sites.
Likely Case
Session hijacking of regular users, credential theft via fake login forms, or defacement of chat conversations.
If Mitigated
Limited to minor disruption if input validation and output encoding are properly implemented.
🎯 Exploit Status
Exploitation requires the ability to send chat messages, which typically requires at least user-level access. The vulnerability is stored XSS, meaning malicious payloads persist in chat conversations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch exists. Implement input validation and output encoding in the chat feature code.
🔧 Temporary Workarounds
Implement Content Security Policy (CSP)
allAdd a Content Security Policy header to restrict script execution sources
Add to web server configuration or HTML meta tag: Content-Security-Policy: script-src 'self'
Input Sanitization
allSanitize all user input in chat messages before storage
Implement HTML entity encoding for user input: & -> &, < -> <, > -> >, " -> ", ' -> '
🧯 If You Can't Patch
- Disable the chat feature entirely if not essential
- Implement a web application firewall (WAF) with XSS protection rules
🔍 How to Verify
Check if Vulnerable:
Test by submitting a chat message with a basic XSS payload like <script>alert('XSS')</script> and check if it executes when viewedCheck Version:
Check the application's version in its documentation or source code filesVerify Fix Applied:
After implementing fixes, test with the same XSS payload to confirm it's properly sanitized and doesn't execute📡 Detection & Monitoring
Log Indicators:
- Chat messages containing script tags or JavaScript code patterns
- Unusual chat activity from single users
Network Indicators:
- HTTP requests with suspicious parameters containing script tags or JavaScript
SIEM Query:
source="web_logs" AND (message="<script" OR message="javascript:" OR message="onerror=" OR message="onload=")