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Insecure Direct Object Reference (IDOR) - User Data Exposure (<=2.0 RC2)

Moderate
ywarnier published GHSA-fp2p-fj6c-x3x9 Apr 10, 2026

Package

composer chamilo/chamilo-lms (Composer)

Affected versions

<= 2.0-RC.2

Patched versions

2.0-RC.3

Description

Summary

Any authenticated user (including ROLE_STUDENT) can enumerate all platform users and access personal information (email, phone, roles) via GET /api/users, including administrator accounts.

Details

The User API GetCollection operation security is is_granted('ROLE_USER'). Since all registered users have ROLE_USER, students can list all users. GET /api/users/{id} also allows viewing any user's details.

Impact

All user emails, phone numbers, and roles exposed to any authenticated user. Admin accounts identifiable for targeted phishing. Prerequisite for Advisory 1 (attacker needs own user ID).

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVE ID

CVE-2026-33736

Weaknesses

Authorization Bypass Through User-Controlled Key

The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. Learn more on MITRE.

Credits