CVE-2026-56727CWE-287CWE-347CWE-391

CVE-2026-56727

published September 25, 2026

CVSS
7.1
EPSS
0%
Percentile
15.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS
7.1 · NONE
CVSS v4.0
7.1 · 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
EPSS
0.00246 · 15.0th percentile
Weaknesses
CWE-287 · Improper Authentication; CWE-347 · Improper Verification of Cryptographic Signature; CWE-391 · Unchecked Error Condition
Published
2026-09-25T22:17Z
References (3)
EPSS history
Timeline
  • 27 SEP 03:26Z
    EPSS moved — → 0%
    epss
  • 25 SEP 17:02Z
    Zammad: PGP signature spoofing via unvalidated verification return
    cvelistv5