Vulnerability Description
Chamilo LMS is an open-source learning management system. In versions prior to 2.0.0-RC.3, a Stored Cross-Site Scripting (XSS) vulnerability exists in the social post attachment upload functionality, where an authenticated user can upload a malicious HTML file containing JavaScript via the /api/social_post_attachments endpoint. The uploaded file is served back from the application at the generated contentUrl without sanitization, content type restrictions, or a Content-Disposition: attachment header, causing the JavaScript to execute in the browser within the application's origin. Because the payload is stored server-side and runs in the trusted origin, an attacker can perform session hijacking, account takeover, privilege escalation (if an admin views the link), and arbitrary actions on behalf of the victim. This issue has been fixed in version 2.0.0-RC.3.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Chamilo | Chamilo Lms | <= 1.11.38 |
Related Weaknesses (CWE)
References
- https://github.com/chamilo/chamilo-lms/commit/7c4965e48769d1d06413836429e386816aPatch
- https://github.com/chamilo/chamilo-lms/commit/da671d66a146887be3a16eabc5dcf0a92cPatch
- https://github.com/chamilo/chamilo-lms/releases/tag/v2.0.0-RC.3ProductRelease Notes
- https://github.com/chamilo/chamilo-lms/security/advisories/GHSA-273p-jw9w-3g22Vendor Advisory
FAQ
What is CVE-2026-34161?
CVE-2026-34161 is a vulnerability with a CVSS score of 5.4 (MEDIUM). Chamilo LMS is an open-source learning management system. In versions prior to 2.0.0-RC.3, a Stored Cross-Site Scripting (XSS) vulnerability exists in the social post attachment upload functionality, ...
How severe is CVE-2026-34161?
CVE-2026-34161 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-34161?
Check the references section above for vendor advisories and patch information. Affected products include: Chamilo Chamilo Lms.