CVE-2025-26153
📋 TL;DR
A stored cross-site scripting (XSS) vulnerability in Chamilo LMS 1.11.28 allows attackers to inject malicious scripts into messages. When victims (including administrators) reply to these messages, the scripts execute in their browser context. This affects all users of the vulnerable version who use the message compose feature.
💻 Affected Systems
- Chamilo LMS
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Administrator account compromise leading to full system takeover, data theft, or deployment of additional malware within the LMS environment.
Likely Case
Session hijacking, credential theft, or unauthorized actions performed in the victim's context, potentially affecting multiple users.
If Mitigated
Limited to isolated user account compromise if proper input validation and output encoding are implemented.
🎯 Exploit Status
Exploitation requires authenticated access to send messages, but the vulnerability is straightforward to exploit once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in commits beb07770d674fcc9db6df0e59aab107678c28682 and d5c29cf39ac30d7364a52bba4036c3e870412066
Vendor Advisory: https://github.com/chamilo/chamilo-lms/commit/beb07770d674fcc9db6df0e59aab107678c28682
Restart Required: No
Instructions:
1. Update to the latest Chamilo LMS version. 2. Apply the specific commits that fix the XSS vulnerability. 3. Clear browser caches and test the message compose feature.
🔧 Temporary Workarounds
Input Validation Filter
allImplement server-side input validation to sanitize message content before storage.
Modify message handling code to strip or encode HTML/JavaScript tags
🧯 If You Can't Patch
- Disable the message compose feature entirely if not essential.
- Implement web application firewall (WAF) rules to block XSS payloads in message content.
🔍 How to Verify
Check if Vulnerable:
Test by sending a message with a simple XSS payload like <script>alert('XSS')</script> and checking if it executes when replying.Check Version:
Check the Chamilo LMS version in the system administration panel or via the web interface.Verify Fix Applied:
After patching, repeat the XSS test to confirm the payload is properly sanitized and does not execute.📡 Detection & Monitoring
Log Indicators:
- Unusual message content containing script tags or JavaScript code in message logs.
- Multiple failed login attempts following message interactions.
Network Indicators:
- Outbound connections to suspicious domains triggered by message replies.
SIEM Query:
Search for logs containing 'message' AND ('script' OR 'javascript' OR 'onload=') in user-generated content fields.🔗 References
- https://gist.github.com/NoSpaceAvailable/234acdf57b5d7b29b2f39090c1686bc8
- https://github.com/chamilo/chamilo-lms/commit/beb07770d674fcc9db6df0e59aab107678c28682
- https://github.com/chamilo/chamilo-lms/commit/d5c29cf39ac30d7364a52bba4036c3e870412066
- https://gist.github.com/NoSpaceAvailable/234acdf57b5d7b29b2f39090c1686bc8
