Zammad 5.2.0 suffers from Incorrect Access Control. Zammad did not correctly perform authorization on certain attachment endpoints. This could be abused by an unauthenticated attacker to gain access to attachments, such as emails or attached files.

Zammad 5.2.0 is vulnerable to privilege escalation. Zammad has a prevention against brute-force attacks trying to guess login credentials. After a configurable amount of attempts, users are invalidated and logins prevented. An attacker might work around this prevention, enabling them to send more than the configured amount of requests before the user invalidation takes place.

In Zammad 5.2.0, customers who have secondary organizations assigned were able to see all organizations of the system rather than only those to which they are assigned.

In Zammad 5.2.0, an attacker could manipulate the rate limiting in the 'forgot password' feature of Zammad, and thereby send many requests for a known account to cause Denial Of Service by many generated emails which would also spam the victim.