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).

A lack of password length restriction in Zammad v5.1.0 allows for the creation of extremely long passwords which can cause a Denial of Service (DoS) during password verification.

A lack of rate limiting in the 'forgot password' feature of Zammad v5.1.0 allows attackers to send an excessive amount of reset requests for a legitimate user, leading to a possible Denial of Service (DoS) via a large amount of generated e-mail messages.

An issue was discovered in Zammad 3.0 through 3.2. The WebSocket server crashes when messages in non-JSON format are sent by an attacker. The message format is not properly checked and parsing errors not handled. This leads to a crash of the service process.