CVE-2026-84673 Cross-site scripting in Jenkins Customizable Header Plugin
Attackers can inject malicious JavaScript via custom SVG icons in the Jenkins Customizable Header Plugin, leading to stored cross-site scripting.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-84673?
CVE-2026-84673 is a high-severity cross-site scripting vulnerability in Jenkins Customizable Header Plugin, published on 2 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Jenkins Customizable Header Plugin 295.v2544b_ca_19b_97 and earlier allows overwriting the plugin's appearance configuration through Stapler data binding, allowing attackers to configure a custom SVG icon containing inline JavaScript, resulting in a stored cross-site scripting (XSS) vulnerability.
Weakness: CWE-79
Which versions are affected by CVE-2026-84673?
How do I fix CVE-2026-84673?
No fix has been published for CVE-2026-84673 yet. Limit exposure of the affected software until one is available.
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-2026-84673 being exploited?
There is no known exploitation of CVE-2026-84673 in the wild and no public exploit code.
Sources
Also known as GHSA-hq87-q544-6grj.