How severe is CVE-2026-102489?

CVE-2026-102489 has a CVSS 4.0 base score of 9.4 (CRITICAL). EPSS estimates a 0.6% probability of exploitation in the next 30 days. It is listed in the CISA Known Exploited Vulnerabilities catalog.

CVE-2026-102489: Undisclosed RCE in Zammad v6.3 and

CISA Known Exploited Vulnerabilities

Zammad GmbH Zammad Session Fixation Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV

2026-10-02

Remediation due

2026-10-05

Required action
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

CISA notes
https://zammad.com/en/product/releases/ ; https://community.zammad.org/t/take-care-local-privilege-escalation-cve-2026-102490-is-reported-as-being-actively-exploited/21297/2 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-102489

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 vulnerability is also present in version 7.0.0 to version 7.1.3, but not exploitable due to environment conditions.

Severity

CVSS 4.0 · CNA8.7 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:A/AU:Y/V:C

CVSS 4.0 · CNA9.4 CRITICAL

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/AU:Y/V:C

SSVC · CISA-ADP

Exploitationactive

Automatableyes

Technical impacttotal

Affected Products

Vendor	Product	Affected versions
Zammad GmbH	Zammad	<6.3.0 (unknown) 6.3.0 to <6.5.4 7.0.0 to <* (unaffected)

References

2 Links

Third-party advisories

Record Details

Published

2026-09-30

Last updated

2026-10-03

Assigner (CNA)

DIVD

Credited to

Earth Grob (Merlon Security); Luke Paris (Merlon Security); Tijmen van der Spijk (Merlon Security); Zohar Cochavi (Merlon Security); Alje Woltjer (Merlon Security); Mischa Rick van Geelen (DIVD); Ralph Horn (DIVD); Max van der Horst (DIVD); Victor Pasman (DIVD); Frank Breedijk (DIVD)

More from Zammad GmbH

CVE-2026-1024909.4

Undisclosed LPE in Zammad v1.5.0 to v7.1.0-alpha

CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.