CVE-2021-21610: Jenkins

Medium severity, CVSS 6.1. EPSS: 1.2% chance of exploitation in the next 30 days.

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not implement any restrictions for the URL rendering a formatted preview of markup passed as a query parameter, resulting in a reflected cross-site scripting (XSS) vulnerability if the configured markup formatter does not prohibit unsafe elements (JavaScript) in markup.

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.