An authenticated user can create a hosts group from the configuration with XSS payload, which will be available for other users. When XSS is stored by an authenticated malicious actor and other users try to search for groups during new host creation, the XSS payload will fire and the actor can steal session cookies and perform session hijacking to impersonate users or take over their accounts.
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.
In Zabbix from 4.0.x before 4.0.28rc1, 5.0.0alpha1 before 5.0.10rc1, 5.2.x before 5.2.6rc1, and 5.4.0alpha1 before 5.4.0beta2, the CControllerAuthenticationUpdate controller lacks a CSRF protection mechanism. The code inside this controller calls diableSIDValidation inside the init() method. An attacker doesn't have to know Zabbix user login credentials, but has to know the correct Zabbix URL and contact information of an existing user with sufficient privileges.
A File Inclusion vulnerability exists in Zabbix 2.0.6 due to inadequate sanitization of request strings in CGI scripts, which could let a remote malicious user execute arbitrary code.
An issue was discovered in zabbix.php?action=dashboard.view&dashboardid=1 in Zabbix through 4.4. An attacker can bypass the login page and access the dashboard page, and then create a Dashboard, Report, Screen, or Map without any Username/Password (i.e., anonymously). All created elements (Dashboard/Report/Screen/Map) are accessible by other users and by an admin.