CVE-2026-34161
MediumCVSS 5.4Exploitation Probability (EPSS)
Low risk12th percentile - higher than 12% of all known CVEs
Summary
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. An authenticated user can upload a malicious HTML file containing JavaScript via the /api/social_post_attachments endpoint. The file is served without sanitization, content type restrictions, or Content-Disposition header, causing JavaScript execution in the application context. This can lead to session hijacking, account takeover, privilege escalation, and other actions. This issue has been fixed in version 2.0.0-RC.3.
Risk Assessment
The risk includes arbitrary JavaScript execution in the application context, which could lead to session hijacking, account takeover, privilege escalation (if an admin views the link), and actions on behalf of the victim.
Recommendation
It is recommended to upgrade to version 2.0.0-RC.3 or later.
Original NVD description (English source)
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.