An exposure of sensitive information vulnerability exists in Jenkins GitHub Authentication Plugin 0.29 and earlier in GithubSecurityRealm/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.

An session fixation vulnerability exists in Jenkins GitHub Authentication Plugin 0.29 and earlier in GithubSecurityRealm.java that allows unauthorized attackers to impersonate another user if they can control the pre-authentication session.