Jenkins 2.218 and earlier, LTS 2.204.1 and earlier did not use a constant-time comparison function for validating connection secrets, which could potentially allow an attacker to use a timing attack to obtain this secret.
https://jenkins.io/security/advisory/2020-01-29/#SECURITY-1659
https://access.redhat.com/errata/RHSA-2020:0683
https://access.redhat.com/errata/RHSA-2020:0681
https://access.redhat.com/errata/RHBA-2020:0675