Jenkins Credentials Plugin 2.1.18 and earlier allowed users with permission to create or update credentials to confirm the existence of files on the Jenkins master with an attacker-specified path, and obtain the certificate content of files containing a PKCS#12 certificate.
https://jenkins.io/security/advisory/2019-05-21/#SECURITY-1322
https://access.redhat.com/errata/RHSA-2019:1636
https://access.redhat.com/errata/RHBA-2019:1605
http://www.securityfocus.com/bid/108462