Gestsup before 3.2.10 allows account takeover through the password recovery functionality (remote). The affected component is the file forgot_pwd.php - it uses a weak algorithm for the generation of password recovery tokens (the PHP uniqueid function), allowing a brute force attack.
https://gestsup.fr/index.php?page=download&channel=beta&version=3.2.10&type=patch
https://gestsup.fr/index.php?page=download
https://dojo.maltem.ca/public/advisories/CVE-2021-31646.html