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.
Metrics
Affected Vendors & Products
References
History
Tue, 29 Sep 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
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| Metrics |
ssvc
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Sat, 26 Sep 2026 10:15:00 +0000
| Type | Values Removed | Values Added |
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| First Time appeared |
Zammad
Zammad zammad |
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| Vendors & Products |
Zammad
Zammad zammad |
Fri, 25 Sep 2026 18:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | Zammad: S/MIME signature verification allows forged sender impersonation | |
| Weaknesses | CWE-290 CWE-295 CWE-347 |
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| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-09-25T18:19:58.735Z
Updated: 2026-09-29T18:08:05.375Z
Reserved: 2026-09-01T20:05:09.424Z
Link: CVE-2026-84465
Updated: 2026-09-29T18:07:57.073Z
Status : Deferred
Published: 2026-09-25T19:17:58.123
Modified: 2026-09-29T19:17:27.050
Link: CVE-2026-84465
No data.