Attack Chain

1. An attacker authenticates to Chamilo LMS as a teacher.
2. The attacker navigates to the gradebook section of a course they have access to.
3. The attacker identifies the URL used to edit an evaluation, noting the editeval parameter and its associated value.
4. The attacker modifies the editeval parameter value to reference an evaluation ID from a different course.
5. The attacker submits the modified request to the Chamilo LMS server.
6. The server, due to the IDOR vulnerability, processes the request without proper authorization checks.
7. The attacker is able to view and modify the settings (name, max score, weight) of the evaluation belonging to the other course.
8. The attacker saves the changes, which are then reflected in the gradebook of the targeted course.

Impact

The successful exploitation of CVE-2026-32930 can lead to unauthorized modification of gradebook evaluation settings. This could result in inaccurate grades, unfair assessment of students, and overall compromise of the learning environment’s integrity. Given that Chamilo LMS is used by educational institutions worldwide, a successful attack could affect a large number of students and teachers. The unauthorized changes could disrupt the educational process and erode trust in the system.

Recommendation

• Upgrade Chamilo LMS to version 1.11.38 or 2.0.0-RC.3 or later to patch CVE-2026-32930, as indicated in the overview.
• Deploy the Sigma rule Detect Chamilo Gradebook Edit Request to identify attempts to exploit this IDOR vulnerability by monitoring for suspicious editeval parameter modifications.
• Review web server logs for requests containing the editeval parameter where the associated value appears out of sequence with the user’s course access, related to the Sigma rule.