Telenia Software TVox versions 26.5.3 and prior (26.x) and 24.9.21 and prior (24.x) contain an authentication bypass vulnerability in set_env.php. The vulnerable function redirectToLoginAdminIRequestHaveAccessToken() derives the current page name from the PHP_SELF variable and skips authentication if the value matches 'login_admin.php'. Attackers can exploit this by appending '/login_admin.php' to any target PHP script path, causing the authentication check to be bypassed. This allows unauthenticated access to all PHP scripts located under the manager HTML directory. The vulnerability requires no authentication or special privileges to exploit, making it highly critical. Organizations using affected versions of Telenia TVox should apply patches or mitigations immediately.