There are 6 open security issues in buster.
5 issues left for the package maintainer to handle:
Zabbix before 5.0 represents passwords in the users table with unsalted MD5.
Zabbix through 4.4.0alpha1 allows User Enumeration. With login requests, it is possible to enumerate application usernames based on the variability of server responses (e.g., the "Login name or password is incorrect" and "No permissions for system access" messages, or just blocking for a number of seconds). This affects both api_jsonrpc.php and index.php.
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.
Zabbix before 3.0.32rc1, 4.x before 4.0.22rc1, 4.1.x through 4.4.x before 4.4.10rc1, and 5.x before 5.0.2rc1 allows stored XSS in the URL Widget.
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.
You can find information about how to handle these issues in the security team's documentation.