CVE-2026-27099 Jenkins has a stored XSS vulnerability in node offline cause description
Attackers with specific permissions can inject malicious scripts into Jenkins agent offline causes, leading to stored XSS and potential session hijacking.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-27099?
CVE-2026-27099 is a high-severity cross-site scripting vulnerability in Jenkins Jenkins, published on 18 Feb 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Jenkins 2.483 through 2.550 (both inclusive), LTS 2.492.1 through 2.541.1 (both inclusive) does not escape the user-provided description of the "Mark temporarily offline" offline cause, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers with Agent/Configure or Agent/Disconnect permission.
Weakness: CWE-79
Which versions are affected by CVE-2026-27099?
5 open source packages ship an affected version, including org.jenkins-ci.main:jenkins-core and jenkins. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.jenkins-ci.main:jenkins-core Maven | From 2.483 | 2.541.2 |
org.jenkins-ci.main:jenkins-core Maven | From 2.483 | 2.541.2 |
org.jenkins-ci.main:jenkins-core Maven | From 2.542 | 2.551 |
org.jenkins-ci.main:jenkins-core Maven | From 2.542 | 2.551 |
jenkins Bitnami | From 2.483.0 | 2.541.2, 2.551.0 |
Products include Jenkins Jenkins.
How do I fix CVE-2026-27099?
Upgrade org.jenkins-ci.main:jenkins-core to a fixed version for your release line: 2.541.2 or 2.551.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-27099 being exploited?
There is no known exploitation of CVE-2026-27099 in the wild and no public exploit code.
Other vulnerabilities in Jenkins Jenkins
- CVE-2024-23897 Jenkins Command Line Interface (CLI) Path Traversal
- CVE-2018-1000861 Jenkins Stapler Web Framework Deserialization of Untrusted Data
- CVE-2017-1000353 Jenkins Remote Code Execution
- CVE-2015-5317 Jenkins User Interface (UI) Information Disclosure
- CVE-2021-21690 Multiple vulnerabilities allow bypassing path filtering of agent-to-controller access control in Jenkins
Sources
Also known as BIT-jenkins-2026-27099, GHSA-85h6-5m3v-gx37, MINI-32fx-4rqj-fg3x, MINI-6x9m-wmr9-vpc3, MINI-9vvp-vqwm-cj8j, MINI-p94v-6qx3-mq7x and 3 more.