CVE-2026-102489

Undisclosed RCE in Zammad v6.3 and higher

CVE CVE-2026-102489
Title Undisclosed RCE in Zammad v6.3 and higher
Case DIVD-2026-00015
Credits
  • Earth Grob (Merlon Security) (finder)
  • Luke Paris (Merlon Security) (finder)
  • Tijmen van der Spijk (Merlon Security) (finder)
  • Zohar Cochavi (Merlon Security) (finder)
  • Alje Woltjer (Merlon Security) (finder)
  • Mischa Rick van Geelen (DIVD) (finder)
  • Ralph Horn (DIVD) (finder)
  • Max van der Horst (DIVD) (finder)
  • Victor Pasman (DIVD) (analyst)
  • Frank Breedijk (DIVD) (analyst)
  • Zammad (remediation developer)
Affected products
Product Affected Unaffected Unknown
Zammad GmbH Zammad on Linux, Docker >= * to < 6.3.0 (semver)
>= 6.3.0 to < 6.5.4 (semver)
>= 7.0.0 to < 7.1.3 (semver)
everything else
CVSS Scenario 1 : GENERAL
Base score 8.7 - HIGH
Attack Vector NETWORK
Attack Complexity> LOW
Attack Requirements NONE
Privileges Required NONE
Confidentiality Impact
Vulnerable system HIGH Subsequent systems LOW
Integrity Impact
Vulnerable system HIGH Subsequent systems LOW
Availability Impact
Vulnerable system HIGH Subsequent systems LOW
Safety impact NOT_DEFINED
Automatable YES
Recovery NOT_DEFINED
Value Density CONCENTRATED
Vulnerability Response effort NOT_DEFINED
Provider Urgency NOT_DEFINED

Scenario 2 : Chained with CVE-2026-102490
Base score 9.4 - CRITICAL
Attack Vector NETWORK
Attack Complexity> LOW
Attack Requirements NONE
Privileges Required NONE
Confidentiality Impact
Vulnerable system HIGH Subsequent systems HIGH
Integrity Impact
Vulnerable system HIGH Subsequent systems HIGH
Availability Impact
Vulnerable system HIGH Subsequent systems HIGH
Safety impact NOT_DEFINED
Automatable YES
Recovery NOT_DEFINED
Value Density CONCENTRATED
Vulnerability Response effort NOT_DEFINED
Provider Urgency NOT_DEFINED
References
Date published 29 Sep 2026 20:00 UTC
Last modified 07 Oct 2026 14:03 UTC

Description

Zammad versions 6.3.0 to 6.5.4 are vulnerable a session hijack vulnerability that leads to remote code execution as the zammad user. The bug is also present in version 7.0.0 to version 7.1.2, but not exploitable due to changes in the underlying framework.

JSON version.