The mcollective-sshkey-security plugin before 0.5.1 for Puppet uses a server-specified identifier as part of a path where a file is written. A compromised server could use this to write a file to an arbitrary location on the client with the filename appended with the string "_pub.pem".
https://puppet.com/security/cve/cve-2017-2298
https://github.com/puppetlabs/mcollective-sshkey-security/blob/0.5.1/CHANGELOG.md