Auth bypass in Chamilo Chamilo-Lms
CVE-2026-40291
Chamilo LMS is an open-source learning management system. In versions prior to 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. The API Platform security expression is_granted('EDIT', object) only verifies record ownership, and the roles field is included in the writable serialization group, enabling any user to set arbitrary roles such as ROLE_ADMIN. Successful exploitation grants full administrative control of the platform, including access to all courses, user data, grades, and administrative settings. This issue has been fixed in version 2.0.0-RC.3.
Vulnerability class: Privilege Escalation
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (35.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 35.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Chamilo Chamilo-Lms — versions < 2.0-RC.3
- Chamilo Lms — versions 2.0.0
Weakness classification (CWE)
References
- github.com/chamilo/chamilo-lms/security/advisories/GHSA-7phx-w897-4c9x (Vendor Advisory)
- github.com/chamilo/chamilo-lms/releases/tag/v2.0.0-RC.3 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-40291?
- CVE-2026-40291 is a high-severity vulnerability in Chamilo Chamilo-Lms, classified under Improper Privilege Management. CVSS score: 8.8/10. Published 2026-04-14.
- How severe is CVE-2026-40291?
- High severity. CVSS v3 base score is 8.8 out of 10.