Incorrect authorization in the certificate-name matching of trapperkeeper-authorization, as used by Puppet Server, in the affected products, allows a client that holds a CA-signed certificate whose name extends or shortens an authorized hostname to be authorized as that host. This enables impersonation of other nodes and, in Puppet Enterprise, access to certificate-authority administration and remote command execution on managed nodes. Exploitation requires a certificate with a colliding name, which the certificate authority issues by approval or autosign.