Jenkins 2.196 and earlier, LTS 2.176.3 and earlier did not escape the SCM tag name on the tooltip for SCM tag actions, resulting in a stored XSS vulnerability exploitable by users able to control SCM tag names for these actions.
https://github.com/advisories/GHSA-7cjc-xppr-xj6x
https://jenkins.io/security/advisory/2019-09-25/#SECURITY-1537%20%281%29