Jenkins 2.251 and earlier, LTS 2.235.3 and earlier does not escape the remote address of the host starting a build via 'Trigger builds remotely', resulting in a stored cross-site scripting (XSS) vulnerability exploitable by users with Job/Configure permission or knowledge of the Authentication Token.
https://jenkins.io/security/advisory/2020-08-12/#SECURITY-1960
http://www.openwall.com/lists/oss-security/2020/08/12/4
http://packetstormsecurity.com/files/160616/Jenkins-2.251-LTS-2.235.3-Cross-Site-Scripting.html