CVE-2017-1000356
Jenkins versions 2.56 and earlier as well as 2.46.1 LTS and earlier are vulnerable to an issue in the Jenkins user database authentication realm: create an account if signup is enabled; or create an account if the victim is an administrator, possibly deleting the existing default admin user in the process and allowing a wide variety of impacts.
Versions it affects
Software versions checked with the free lookup that CVE-2017-1000356 applies to, and the release that fixes it where the sources name one.
Is this running somewhere in your estate?
The Vulnerability Reporter inventories every machine and tells you when an advisory like this one applies to you.