---
id: "CVE-2026-102489"
kind: "vulnerability"
aliases: ["CVE-2026-102489"]
title: "Zammad versions 6.3.0 to 6.5.4 are vulnerable a session hijack vulnerability that leads to remote code execution as\u2026"
severity: "critical"
cvss: 9.8
epss: null
exploited: true
status: "open"
category: "package"
products: [{"name": "Zammad GmbH Zammad", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "Zammad", "fixed": ["6.5.5", "7.2.0"], "affected": ">= 6.3.0, <= 6.5.4", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "helpdesk", "kev", "package", "rce", "self-hosted", "session-fixation", "zammad"]
not_affected_if: ["managed-hosting", "version-7.0-or-later", "zammad-saas"]
published_at: "2026-09-30T17:16:40+00:00"
first_seen_at: "2026-10-23T19:11:50+00:00"
updated_at: "2026-10-23T23:44:52+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-102489", "first_seen_at": "2026-10-23T19:11:50+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-23T20:27:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-102489", "first_seen_at": "2026-10-23T23:44:52+00:00"}]
---

# Zammad versions 6.3.0 to 6.5.4 are vulnerable a session hijack vulnerability that leads to remote code execution as…

Zammad 6.3.0 to 6.5.4 (end-of-support) has a session fixation/hijack flaw giving RCE as the zammad user; CVSS vectors say no privileges needed. Exploited in the wild (CISA KEV, DIVD breach by chained CVE-2026-102490 root escalation). Zammad 7.0+ is not exploitable in practice. SaaS needs no action.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Zammad GmbH Zammad affected ? fixed ?
- vendor:Zammad affected >= 6.3.0, <= 6.5.4 fixed 6.5.5, 7.2.0

## How to check

Check version: self-hosted Zammad 6.3.0 to 6.5.4 is vulnerable (Admin > System > Version, or 'zammad run rails r "puts Zammad::Version.get"'). Versions before 6.3.0 are unknown per DIVD. Run DIVD's log-check script from the DIVD-2026-00015 page for IoCs.

## Fix

Upgrade to Zammad 7.2.2 (recommended; 7.2.0 includes the hardening change). If stuck on 6.5, update to 6.5.4 -> 6.5.5 emergency release, which requires switching to the new package repository first. Restrict server access; if compromised assume root (CVE-2026-102490) and rebuild.

## Timeline

- 2026-10-23T19:11:50+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-102489
- 2026-10-23T20:27:51+00:00 analyst — Vendor advisory (zammad.com, 2026-10-05) and DIVD-2026-00015: Zammad 6.3.0-6.5.4 exploitable (WebSocket session hijack to RCE as zammad user); 7.0+ not exploitable in practice; fix is 6.5.5 emergency release (new repo) or 7.2.x. Severity raised: CISA KEV, exploited in the wild, CVSS 9.8 (NVD) / 9.4 v4 with PR:N. Unauthenticated per CVSS vectors; vendor advisory does not spell out the mechanism. Chained with CVE-2026-102490 (local priv-esc to root, DEB/RPM packages only).
- 2026-10-23T23:44:52+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-102489

## Documents

- [advisory] Zammad advisory CVE-2026-102489 & CVE-2026-102490 https://zammad.com/en/advisories/cve-2026-102489-cve-2026-102490
- [advisory] DIVD-2026-00015 case page https://csirt.divd.nl/cases/DIVD-2026-00015/
- [describes] CISA KEV additions 2026-10-02 https://www.cisa.gov/news-events/alerts/2026/10/02/cisa-adds-two-known-exploited-vulnerabilities-catalog
- [discussion] Sysdig: AI agent exploits Zammad zero-days in DIVD breach https://www.sysdig.com/blog/ai-agent-exploits-zammad-zero-days-in-divd-breach-what-we-know-and-how-to-detect-it
- [fix] Zammad 6.5.5 Critical Security Update https://zammad.com/en/product/releases/6-5-5

## From the sources

Zammad GmbH Zammad contains a session fixation vulnerability that can lead to remote code execution as the zammad user. This vulnerability can be chained with CVE-2026-102490.

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_