Jenkins 2.196 and earlier, LTS 2.176.3 and earlier did not escape the reason why a queue items is blcoked in tooltips, resulting in a stored XSS vulnerability exploitable by users able to control parts of the reason a queue item is blocked, such as label expressions not matching any idle executors.
References:- https://nvd.nist.gov/vuln/detail/CVE-2019-10404
- http://www.openwall.com/lists/oss-security/2019/09/25/3
- https://jenkins.io/security/advisory/2019-09-25/#SECURITY-1537
- https://github.com/jenkinsci/jenkins/commit/8c8d0143309667bcada8ebc36e40dab4c65c6eb2
- https://github.com/advisories/GHSA-9qgf-4fpf-cmh2