CVE Catalog

CVE-2026-84465

HighCVSS 7.1
Published: Translated: NVD NIST

Summary

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.

Risk Assessment

An attacker can impersonate a trusted sender and send forged messages that appear authentic. This may lead to phishing, fraud, or misleading customer support staff.

Recommendation

Update Zammad to version 7.1.2 or later. Until then, do not rely solely on the S/MIME signature indicator and verify sender identity through other channels.

Other vulnerabilities in Zammad

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS