CVE-2026-84465

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.

CVSS

No CVSS.

References

Link	Resource
https://github.com/zammad/zammad/commit/9a07d0b8214ac4e8e10c23fce71d613bd0625524
https://github.com/zammad/zammad/security/advisories/GHSA-m9ff-hjr3-93h4

Configurations

No configuration.

History

25 Sep 2026, 19:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-09-25 19:17

Updated : 2026-09-29 19:17

NVD link : CVE-2026-84465

Mitre link : CVE-2026-84465

CVE.ORG link : CVE-2026-84465

JSON object : View

Products Affected

No product.

CWE

CWE-290

Authentication Bypass by Spoofing

CWE-295

Improper Certificate Validation

CWE-347

Improper Verification of Cryptographic Signature

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