CVE-2021-21639
Jenkins 2.286 and earlier, LTS 2.277.1 and earlier does not validate the type of object created after loading the data submitted to the `config.xml` REST API endpoint of a node, allowing attackers with Computer/Configure permission to replace a node with one of a different type.
Versions it affects
Software versions checked with the free lookup that CVE-2021-21639 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.