An issue was discovered in Zammad before 6.2.0. When listing tickets linked to a knowledge base answer, or knowledge base answers of a ticket, a user could see entries for which they lack permissions.

An issue was discovered in Zammad before 6.2.0. An attacker can trigger phishing links in generated notification emails via a crafted first or last name.

An issue was discovered in Zammad before 6.2.0. Due to lack of rate limiting in the "email address verification" feature, an attacker could send many requests for a known address to cause Denial Of Service (generation of many emails, which would also spam the victim).

An issue was discovered in Zammad before 6.2.0. In several subsystems, SSL/TLS was used to establish connections to external services without proper validation of hostname and certificate authority. This is exploitable by man-in-the-middle attackers.

An issue was discovered in Zammad before 6.2.0. It uses the public endpoint /api/v1/signshow for its login screen. This endpoint returns internal configuration data of user object attributes, such as selectable values, which should not be visible to the public.