What is CVE-2026-42523?

CVE-2026-42523 is a critical-severity vulnerability in Jenkins GitHub, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2026-04-29.

How severe is CVE-2026-42523?

Critical severity. CVSS v3 base score is 9.0 out of 10.

XSS in Jenkins GitHub

CVE-2026-42523

Jenkins GitHub Plugin 1.46.0 and earlier improperly processes the current job URL as part of JavaScript implementing validation of the feature "GitHub hook trigger for GITScm polling", resulting in a stored cross-site scripting (XSS) vulnerability exploitable by non-anonymous attackers with Overall/Read permission.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-04-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (40.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 40th percentile — 40.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

Jenkins GitHub
Jenkins Project GitHub Plugin — versions 0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

www.jenkins.io/security/advisory/2026-04-29/ (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-42523?: CVE-2026-42523 is a critical-severity vulnerability in Jenkins GitHub, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2026-04-29.
How severe is CVE-2026-42523?: Critical severity. CVSS v3 base score is 9.0 out of 10.