CVE-2026-102489
CVE-2026-102489 is a security flaw in Zammad GmbH Zammad. Attackers can run their own code on Zammad GmbH Zammad. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 2 Oct 2026.[1]
Zammad GmbH Zammad is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Fixed in version 6.5.4 of Zammad.
Description
CISA calls it a session fixation in Zammad GmbH Zammad. In its words: “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.”[1]
The CVE record adds: “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.”[2]
The underlying weakness is CWE-384, in MITRE’s list of common software weaknesses.
It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record lists one fixed version: everything before it is affected.[2]
| Product | Fixed in |
|---|---|
| Zammad | 6.5.4 |
Most families won’t have Zammad GmbH Zammad; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 2 Oct 2026, 2 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 5 Oct 2026 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 22%. That’s in the top 3% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Zammad GmbH has published a fix or advice.[3] CISA’s 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).”[1]
- Check whether you use it.Zammad GmbH Zammad is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed (fixed in version 6.5.4 of Zammad), or not in use. CISA gave US government agencies until 5 Oct 2026 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 22%.[4] |
See also
Other Zammad GmbH Zammad flaws
- CVE-2026-102490: improper privilege management ·
Added the same day
- CVE-2026-102490, Zammad GmbH Zammad: improper privilege management ·
References
- ^ Cybersecurity and Infrastructure Security Agency. “Zammad GmbH Zammad Session Fixation Vulnerability”. Known Exploited Vulnerabilities Catalog, added 2 Oct 2026.
- ^ National Institute of Standards and Technology. “CVE-2026-102489 Detail”. National Vulnerability Database, published 30 Sep 2026.
- ^ Zammad GmbH. Advisories and fixes: zammad.com, community.zammad.org, zammad.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.225, percentile 97.7, 31 Oct 2026.
- CVE Program. “CVE-2026-102489”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.