CVE-2026-34602 | Chamilo LMS: IDOR in /api/course_rel_users Allows Unauthorized Enrollment of Arbitrary Users into Courses

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.

Published: 2026-04-14 Last update: 2026-04-22 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-34602 is rated Low Risk (31.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.03%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-34602

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-15 — 0.03% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-34602

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.1 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 4.2 [email protected]

Weakness enumeration for CVE-2026-34602

Affected software / configurations for CVE-2026-34602

Vendor Product Version Raw CPE
chamilo chamilo_lms <= 1.11.38 cpe:2.3:a:chamilo:chamilo_lms:*:*:*:*:*:*:*:*
chamilo chamilo_lms 2.0.0 cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha1:*:*:*:*:*:*
chamilo chamilo_lms 2.0.0 cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha2:*:*:*:*:*:*
chamilo chamilo_lms 2.0.0 cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha3:*:*:*:*:*:*
chamilo chamilo_lms 2.0.0 cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha4:*:*:*:*:*:*
chamilo chamilo_lms 2.0.0 cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha5:*:*:*:*:*:*
chamilo chamilo_lms 2.0.0 cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta1:*:*:*:*:*:*
chamilo chamilo_lms 2.0.0 cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta2:*:*:*:*:*:*
chamilo chamilo_lms 2.0.0 cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta3:*:*:*:*:*:*
chamilo chamilo_lms 2.0.0 cpe:2.3:a:chamilo:chamilo_lms:2.0.0:rc1:*:*:*:*:*:*
chamilo chamilo_lms 2.0.0 cpe:2.3:a:chamilo:chamilo_lms:2.0.0:rc2:*:*:*:*:*:*

References for CVE-2026-34602

cvelogic Threat Intelligence