CVE-2026-24399
📋 TL;DR
This vulnerability allows attackers to inject malicious HTML/JavaScript payloads into ChatterMate chatbot inputs, which are then executed in users' browsers. This enables theft of sensitive client-side data like localStorage tokens and cookies. Users of ChatterMate versions 1.0.8 and below are affected.
💻 Affected Systems
- ChatterMate
📦 What is this software?
Chattermate by Chattermate
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of user sessions, theft of authentication tokens and sensitive data stored in browser storage, potential account takeover, and lateral movement within the application.
Likely Case
Session hijacking, theft of user-specific data from localStorage and cookies, potential credential theft if sensitive information is stored client-side.
If Mitigated
Limited impact with proper input validation and output encoding, though some client-side data exposure may still occur.
🎯 Exploit Status
The advisory includes specific payload examples (<iframe> with javascript: URI), making exploitation straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.0.9
Vendor Advisory: https://github.com/chattermate/chattermate.chat/security/advisories/GHSA-72p3-w95w-q3j4
Restart Required: Yes
Instructions:
1. Download version 1.0.9 from the official repository. 2. Replace existing ChatterMate installation with the patched version. 3. Restart the ChatterMate service. 4. Verify the fix by testing with known malicious payloads.
🔧 Temporary Workarounds
Input Sanitization
allImplement server-side input validation to strip or escape HTML/JavaScript content from chat inputs.
Content Security Policy
allImplement strict CSP headers to prevent execution of inline scripts and restrict iframe sources.
🧯 If You Can't Patch
- Implement WAF rules to block requests containing malicious HTML/JavaScript patterns in chat inputs.
- Disable or restrict chatbot functionality until patching is possible.
🔍 How to Verify
Check if Vulnerable:
Test by submitting an <iframe> payload with javascript: URI as chat input and checking if it executes in the browser.Check Version:
Check package.json or application metadata for version number, or run: npm list chattermate (if installed via npm)Verify Fix Applied:
After patching, test with the same malicious payload to confirm it's properly sanitized or blocked.📡 Detection & Monitoring
Log Indicators:
- Unusual chat input patterns containing HTML tags, iframe elements, or javascript: URIs
- Increased error logs from input validation failures
Network Indicators:
- HTTP requests with chat payloads containing suspicious HTML/JavaScript content
SIEM Query:
source="chat_logs" AND (message="*<iframe*" OR message="*javascript:*")