Atlas-Livre contains an improper access control vulnerability in the admin controllers under Espace_admin/controleur/ that allows unauthenticated attackers to bypass session-based authentication guards by sending raw HTTP requests that ignore redirects. Attackers can invoke destructive admin actions such as record deletion by requesting controller endpoints with GET parameters like supp, because the PHP header() redirect is never followed by an exit or die call, allowing all subsequent code including database operations to execute regardless of session state.