After the initial setup process, some steps of setup.php file are reachable not only by super-administrators, but by unauthenticated users as well. Malicious actor can pass step checks and potentially change the configuration of Zabbix Frontend.
https://support.zabbix.com/browse/ZBX-20384
https://lists.debian.org/debian-lts-announce/2022/02/msg00008.html