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.