In Jenkins OpenID Connect Provider Plugin 96.vee8ed882ec4d and earlier the generation of build ID Tokens uses potentially overridden values of environment variables, in conjunction with certain other plugins allowing attackers able to configure jobs to craft a build ID Token that impersonates a trusted job, potentially gaining unauthorized access to external services.

Jenkins OpenId Connect Authentication Plugin 4.452.v2849bd3945fa and earlier, except 4.438.440.v3f5f201de5dc, treats usernames as case-insensitive, allowing attackers on Jenkins instances configured with a case-sensitive OpenID Connect provider to log in as any user by providing a username that differs only in letter case, potentially gaining administrator access to Jenkins.