Jenkins OpenId Connect Authentication Plugin 2.6 and earlier stores a password of a local user account used as an anti-lockout feature in a recoverable format, allowing attackers with access to the Jenkins controller file system to recover the plain text password of that account, likely gaining administrator access to Jenkins.
Jenkins OpenId Connect Authentication Plugin 2.6 and earlier improperly determines that a redirect URL after login is legitimately pointing to Jenkins, allowing attackers to perform phishing attacks.