Previous versions of Puppet Agent didn't verify the peer in the SSL connection prior to downloading the CRL. This issue is resolved in Puppet Agent 6.4.0.
{ "versions": [ { "introduced": "6.0.0" }, { "fixed": "6.4.0" } ] }
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-11751.json"