Vulnerability details

Zammad is a web based open source helpdesk/customer support system. Prior to 7.1.2, when Zammad checks the digital signature on an incoming S/MIME-signed email, it does not verify that the signing certificate is genuinely trusted, it only checks whether a certificate with a matching name is already stored in the system. An attacker can create their own certificate using the name of a real, previously trusted sender and use it to send a forged email. Zammad will display that email with the same "validly signed" indicator as a genuine message from the real sender, even though the attacker never had access to that sender's actual certificate or private key. This issue is fixed in version 7.1.2.

• https://github.com/zammad/zammad/security/advisories/GHSA-m9ff-hjr3-93h4 x_refsource_CONFIRM
• https://github.com/zammad/zammad/commit/9a07d0b8214ac4e8e10c23fce71d613bd0625524 x_refsource_MISC