In the case of instances where the SAML SSO authentication is enabled (non-default), session data can be modified by a malicious actor, because a user login stored in the session was not verified. Malicious unauthenticated actor may exploit this issue to escalate privileges and gain admin access to Zabbix Frontend. To perform the attack, SAML authentication is required to be enabled and the actor has to know the username of Zabbix user (or use the guest account, which is disabled by default).

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.

An authenticated Zabbix user (including Guest) is able to cause disproportionate CPU load on the webserver by sending specially crafted parameters to /imgstore.php, leading to potential denial of service.

An authenticated Zabbix Super Admin can exploit the oauth.authorize action to read arbitrary files from the webserver leading to potential confidentiality loss.