Improper Certificate Validation in Zammad - CVE-2026-84465
Published: October 3, 2026
Vulnerability identifier: #VU153219
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-84465
CWE-ID: CWE-295
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to impersonate a trusted sender.
The vulnerability exists due to improper certificate validation in S/MIME signature verification when checking incoming S/MIME-signed emails. A remote attacker can create a certificate using the name of a previously trusted sender and send a forged signed email to impersonate a trusted sender.
User interaction is required.
Affected software
Zammad
How to mitigate CVE-2026-84465
Install security update from vendor's website.
Zammad - update to 7.1.2