Vulnerability · Published Sep 25, 2026 · Assigned by GitHub_M

CVE-2026-56727Zammad: PGP signature spoofing via unvalidated verification return

High 7.1

In plain English

A high-severity improper authentication in zammad from zammad. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities).

Severity (CVSS 4.0)7.1High

Exploit odds (30 days)0.2%top 84.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
zammad	zammad	< 7.0.2

Weakness: CWE-287, CWE-347, CWE-391 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

References

https://github.com/zammad/zammad/security/advisories/GHSA-56jc-34c8-2xq4 x_refsource_CONFIRM
https://github.com/zammad/zammad/commit/4a9dd5f8a85948c5a2f96f6479d785153aac05d7 x_refsource_MISC
https://github.com/zammad/zammad/releases/tag/7.0.2 x_refsource_MISC