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TI-2026-40900 Aliases CVE-2026-56727

Zammad: PGP signature spoofing via unvalidated verification return

Priority LOW 37CWE-287Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-287.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00246 15th percentileScored 2026-11-07
Fix Fixed zammad (zammad): 7.0.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Zammad GmbHzammadbefore 7.0.27.0.2Patch availableCNA
  • zammad VendorZammad GmbH Affected before 7.0.2 Fixed in 7.0.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:zammad:zammad:*:*:*:*:*:*:*:*——Zammad GmbH
  • cpe:2.3:a:zammad:zammad:*:*:*:*:*:*:*:* Versions — — ·Zammad GmbH

Remediation

  • Fix · CNA zammad (zammad) Fixed in 7.0.2

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-56727

References

Other 3

  • TI-2026-65406 Local privilege escalation in Zammad v1.5.0 to v7.2.2 installed via DEB or RPM package KEVCVSS 4.0CRITICAL 9.4
  • TI-2026-65405 Undisclosed RCE in Zammad v6.3 and higher KEVCVSS 4.0CRITICAL 9.4
  • TI-2024-22252 An issue was discovered in Zammad before 6.3.0. CVSS 3.1CRITICAL 9.1
  • TI-2026-11233 Zammad 7.0.1 - Improper authorization in ticket article attachment cloning CVSS 4.0HIGH 7.1
  • TI-2022-23785 A vulnerability in Zammad v5.3.0 allows attackers to execute arbitrary code or escalate… CVSS 3.1CRITICAL 9.8
  • TI-2026-58043 Zammad: Account takeover via unverified email matching during SSO auto-link CVSS 4.0CRITICAL 9.1
See all 123 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences