Auth bypass in Chamilo Chamilo-Lms
CVE-2026-34602
Chamilo LMS is an open-source learning management system. In versions prior to 2.0.0-RC.3, the /api/course_rel_users endpoint is vulnerable to Insecure Direct Object Reference (IDOR), allowing an authenticated attacker to modify the user parameter in the request body to enroll any arbitrary user into any course without proper authorization checks. The backend trusts the user-supplied input for the user field and performs no server-side verification that the requester owns the referenced user ID or has permission to act on behalf of other users. This enables unauthorized manipulation of user-course relationships, potentially granting unintended access to course materials, bypassing enrollment controls, and compromising platform integrity. This issue has been fixed in version 2.0.0-RC.3.
Vulnerability class: IDOR (Insecure Direct Object Reference)
EPSS: 0.002 (10.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N.
Affected products
- Chamilo Chamilo-lms — versions < 2.0.0-RC.3
- Chamilo Chamilo_lms — versions 2.0.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-34602?
- CVE-2026-34602 is a high-severity vulnerability in Chamilo Chamilo-Lms, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 7.1/10. Published 2026-04-14.
- How severe is CVE-2026-34602?
- High severity. CVSS v3 base score is 7.1 out of 10.