---
title: "CVE-2026-102489: Zammad GmbH Zammad Session Fixation Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-102489/
description: "CVE-2026-102489 (Zammad GmbH Zammad): Exploited in the wild (CISA KEV). Zammad versions 6.3.0 to 6.5.4 are vulnerable a session hijack vulnerability that…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-09-30
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-102489"
kev: true
cvss: 8.7
epss: 0.01255
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-102489: Zammad GmbH Zammad Session Fixation Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Zammad GmbH Zammad. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-10-02, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-10-05 ; treat that as the outer limit, not the target.
- EPSS 1.3% , percentile 69: FIRST’s model estimates a 1.3% chance of exploitation activity in the next 30 days, higher than 69% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Editorial verdict: Act now. Zammad CVE-2026-102489/102490: Exploited RCE-to-Root Chain — Self-hosted Zammad on 6.x is remotely exploitable and was used in a real breach: upgrade to 7.2.2 today (6.5.5 only as a stopgap), and patch DEB/RPM installs of any version to close the root escalation.

## What it is

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.

## Affected products (CVE record)

- Zammad GmbH Zammad: 6.3.0 < 6.5.4

## Severity

- DIVD CVSS 4.0: 8.7 `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`
- DIVD CVSS 4.0: 9.4 `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`

## Exploitation

- CISA KEV: added 2026-10-02; federal due date 2026-10-05. Known ransomware use: Unknown.
- CISA 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 SSVC assessment: exploitation active , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.26% probability of exploitation activity in the next 30 days; percentile 69.

## Sources

- [zammad.com](https://zammad.com/en/advisories/cve-2026-102489-cve-2026-102490)
- [Listed in CISA KEV notes (zammad.com)](https://zammad.com/en/product/releases/)
- [Listed in CISA KEV notes (community.zammad.org)](https://community.zammad.org/t/take-care-local-privilege-escalation-cve-2026-102490-is-reported-as-being-actively-exploited/21297/2)
- [CVE.org record CVE-2026-102489](https://www.cve.org/CVERecord?id=CVE-2026-102489)
- [NVD entry CVE-2026-102489](https://nvd.nist.gov/vuln/detail/CVE-2026-102489)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-102489)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk)
- [csirt.divd.nl](https://csirt.divd.nl/DIVD-2026-00015)
- [csirt.divd.nl](https://csirt.divd.nl/CVE-2026-102489)

---
Source page: https://erroneo.us/security/cve/CVE-2026-102489/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt