Jenkins Blue Ocean Plugin 1.23.2 and earlier provides an undocumented feature flag that, when enabled, allows an attacker with Job/Configure or Job/Create permission to read arbitrary files on the Jenkins controller file system.
https://www.jenkins.io/security/advisory/2020-09-16/#SECURITY-1956
http://www.openwall.com/lists/oss-security/2020/09/16/3