High severity · published Sep 25, 2026
CVE-2026-56727
Zammad: PGP signature spoofing via unvalidated verification return
7.1
CVSS
0.2%
EPSS
No
On KEV
Description
Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.2, summary In Zammad's inbound PGP email processing, the return value of the gpg verification call was silently discarded. Regardless of whether gpg reported a valid, invalid, or missing signature, the handler unconditionally wrote sign: { success: true, comment: "Good signature" } to the article's security preferences. Impact Any sender could tamper with the body of a multipart/signed PGP email, or craft a message with an entirely fabricated or mismatched signature, and Zammad would display it to the recipient as cryptographically verified with a "Good signature" label. Users and agents relying on Zammad's signature indicator to confirm message authenticity and integrity would be misled into trusting modified or forged content. The vulnerability affects all inbound PGP-signed emails processed while the PGP integration is enabled. This issue is fixed in version 7.0.2.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 16% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZA
zammad · zammad
< 7.0.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-56727
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-56727
github.com
https://github.com/zammad/zammad/commit/4a9dd5f8a85948c5a2f96f6479d785153aac05d7
github.com
https://github.com/zammad/zammad/releases/tag/7.0.2
github.com
https://github.com/zammad/zammad/security/advisories/GHSA-56jc-34c8-2xq4
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