Dmitry Sobolev

**Name of the Vulnerable Software and Affected Versions** Zammad versions prior to 3.4.1 **Description** An issue was discovered in the SSO endpoint of Zammad, allowing an authentication bypass via a crafted header when SSO is not configured. This enables an attacker to create a valid and authenticated session, which can be used to perform actions in the name of other users. **Recommendations** For versions prior to 3.4.1, update to version 3.4.1 or later to resolve the issue. As a temporary workaround, consider disabling the SSO endpoint until a patch is available. Restrict access to the SSO endpoint to minimize the risk of exploitation.