Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:NSummary
CVE-2026-34602 is a high-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability in Chamilo Chamilo Lms. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 11th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-24 (Access Control Decisions) and AC-3 (Access Enforcement) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
Chamilo LMS, an open-source learning management system, contains an Insecure Direct Object Reference (IDOR) vulnerability (CWE-639) in versions prior to 2.0.0-RC.3, tracked as CVE-2026-34602. The issue affects the /api/course_rel_users endpoint, where the backend trusts user-supplied input in the user field of the request body without performing server-side verification that the requester owns the referenced user ID or has permission to act on behalf of other users. This flaw has a CVSS v3.1 base score of 7.1 (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N).
An authenticated attacker with low privileges can exploit this vulnerability over the network with low complexity and no user interaction required. By modifying the user parameter in the request body, the attacker can enroll any arbitrary user into any course, enabling unauthorized manipulation of user-course relationships. Successful exploitation grants unintended access to course materials, bypasses enrollment controls, and compromises platform integrity.
The vulnerability is fixed in Chamilo LMS version 2.0.0-RC.3. Mitigation involves updating to this release or later, as detailed in the GitHub security advisory (GHSA-x373-8j9j-g5pj) and the associated commit fixes and release notes.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-22718
Vulnerability Data
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Enforcing approved authorizations on every access request structurally stops a user-controlled key from reaching another user's data.
Requiring explicit access-control decisions on each request blocks unauthorized key-driven access.
Least-privilege restrictions limit the scope of data reachable even if a key check is bypassed.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Enforcing authorization policy and least privilege directly blocks user-controlled key tampering that bypasses access checks.
Logical access controls prevent unauthorized data access that results from missing authorization checks on object references.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect missing authorization checks but does not prevent the weakness in production.
Information access restriction explicitly enforces that users may only retrieve data they are authorized to see, directly addressing user-controlled key bypass.
Access control policy directly requires enforcement of authorization rules that prevent unauthorized access via manipulated keys.
Managing access rights includes ensuring users can only access their own records and not bypass authorization by altering identifiers.
Privileged access rights control restricts what data each user may access, mitigating direct object reference attacks.
Secure development lifecycle includes authorization design but does not itself implement runtime access checks.