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.
Other vulnerabilities in Chamilo LMS
See all- CVE-2026-39878Critical
Chamilo LMS versions 1.11.38 and earlier contain a stored cross-site scripting vulnerability in the user registration form. An unauthenticated attacker can execute arbitrary JavaScript in an administrator's browser session, leading to full platform admin account takeover.
- CVE-2026-82535Medium
Chamilo LMS before 1.11.42 and 3.0.0 contains a stored cross-site scripting vulnerability that allows unauthenticated attackers to inject malicious script payloads into survey answers by computing deterministic invitation codes and bypassing authorization checks in the survey submission endpoint. The scripts are rendered in reporting views and execute in the browser sessions of teachers or administrators.
- CVE-2026-40291High
In Chamilo LMS prior to version 2.0.0-RC.3, an insecure direct object modification vulnerability in the PUT /api/users/{id} endpoint allows any authenticated user with ROLE_STUDENT to escalate their privileges to ROLE_ADMIN by modifying the roles field on their own user record.
- CVE-2026-35196High
In Chamilo LMS prior to 2.0.0-RC.3, an OS command injection exists in main/inc/ajax/gradebook.ajax.php in the export_all_certificates action. The course code from the session is concatenated into shell_exec() without sanitization, allowing arbitrary command execution via session manipulation.
- CVE-2026-34602High
An Insecure Direct Object Reference (IDOR) vulnerability in the /api/course_rel_users endpoint of Chamilo LMS prior to version 2.0.0-RC.3. An authenticated attacker can modify the user parameter in the request to enroll any arbitrary user into any course without proper authorization. The backend trusts user-supplied input and does not verify if the requester has permission to act on behalf of other users.
- CVE-2026-34370Medium
Chamilo LMS versions prior to 2.0.0-RC.3 have an IDOR vulnerability in the notebook module. An authenticated student can read private notes of any other user by manipulating the notebook_id parameter in the editnote action. The application fetches note content without ownership verification.
- CVE-2026-34160High
Chamilo LMS before version 2.0.0-RC.3 has a Server-Side Request Forgery (SSRF) vulnerability in the PENS plugin endpoint. The endpoint is accessible without authentication and accepts a package-url parameter that the server fetches without filtering private IP addresses.
- CVE-2026-33715High
Chamilo LMS version 2.0-RC.2 has an unauthenticated endpoint install.ajax.php that accepts arbitrary Symfony Mailer DSN, enabling SSRF into internal networks via SMTP. An unauthenticated attacker can also use the server as an open email relay.
- CVE-2023-39582Medium
SQL Injection vulnerability in Chamilo LMS versions 1.11 through 1.11.20 allows a remote privileged attacker to obtain sensitive information via the import sessions functions.
- CVE-2023-31807Medium
A Cross-Site Scripting vulnerability was found in Chamilo LMS version 1.11.18. It allows a local attacker to execute arbitrary code via a crafted payload in the personal notes function.
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.

