CVEs / CVE-2026-102489
CVE-2026-102489: Zammad GmbH Zammad Session Fixation Vulnerability
- Known exploited in the CISA KEV catalog since 2 Oct 2026
- critical 9.8 CVSS 3.1 (NVD)
- EPSS 22.4% chance of exploitation in the next 30 days, higher than 97% of CVEs (30 Oct 2026)
- Last changed at its sources
Are you affected? Check your servers with Stackurity: it lists the software on each server and the vulnerabilities to fix first.
Check your servers with Stackurity Already using Stackurity? Search for CVE-2026-102489
Summary
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.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Zammad GmbH Zammad | from 6.3.0, before 6.5.4 | 6.5.4 |
Exploitation
| In CISA KEV since | 2 Oct 2026 |
|---|---|
| Due date for US federal agencies | 5 Oct 2026 |
| Used in ransomware campaigns | Unknown |
| 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. |
Severity
| CVSS 3.1 | 9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HScored by NVD |
|---|---|
| Weakness | CWE-384 |
References
- CVE-2026-102489 on NVD
- CVE-2026-102489 in the CISA KEV catalog
- https://zammad.com/en/product/releases/ (cited by CISA)
- https://community.zammad.org/t/take-care-local-privilege-escalation-cve-2026-102490-is-reported-as-being-actively-exploited/21297/2 (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (cited by CISA)
- https://community.zammad.org/t/take-care-local-privilege-escalation-cve-2026-102490-is-reported-as-being-actively-exploited/21297/2 Vendor Advisory
- https://csirt.divd.nl/CVE-2026-102489 Third Party Advisory
- https://csirt.divd.nl/DIVD-2026-00015 Third Party Advisory
- https://zammad.com/en/advisories/cve-2026-102489-cve-2026-102490 Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-102489 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.