CVE-2021-21603: Jenkins

Medium severity, CVSS 5.4. EPSS: 1% chance of exploitation in the next 30 days.

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not escape notification bar response contents, resulting in a cross-site scripting (XSS) vulnerability.

Affected products

• Jenkins Jenkins: up to and including 2.263.1; up to and including 2.274

Published 2021-01-13. Last modified 2026-06-17.