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.

Jenkins OpenId Connect Authentication Plugin 4.452.v2849b_d3945fa_ 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.

Jenkins OpenId Connect Authentication Plugin 4.418.vccc7061f5b_6d and earlier does not invalidate the previous session on login.

Jenkins OpenId Connect Authentication Plugin 4.354.v321ce67a_1de8 and earlier does not check the `aud` (Audience) claim of an ID Token, allowing attackers to subvert the authentication flow, potentially gaining administrator access to Jenkins.

Jenkins OpenId Connect Authentication Plugin 4.354.v321ce67a_1de8 and earlier does not check the `iss` (Issuer) claim of an ID Token, allowing attackers to subvert the authentication flow, potentially gaining administrator access to Jenkins.

Jenkins OpenId Connect Authentication Plugin 2.4 and earlier does not invalidate the previous session on login.

An exposure of sensitive information vulnerability exists in Jenkins OpenId Connect Authentication Plugin 1.4 and earlier in OicSecurityRealm/config.jelly that allows attackers able to view a Jenkins administrator's web browser output, or control the browser (e.g. malicious extension) to retrieve the configured client secret.