A server-side request forgery vulnerability exists in Jenkins Git Plugin 3.9.0 and older in AssemblaWeb.java, GitBlitRepositoryBrowser.java, Gitiles.java, TFS2013GitRepositoryBrowser.java, ViewGitWeb.java that allows attackers with Overall/Read access to cause Jenkins to send a GET request to a specified URL.
https://github.com/advisories/GHSA-53wf-vqf9-cgf2
https://jenkins.io/security/advisory/2018-06-04/#SECURITY-810