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.
https://puppet.com/security/cve/CVE-2018-11751
Source: Mitre, NVD
Published: 2019-12-16
Updated: 2020-04-07
Base Score: 4.8
Vector: CVSS2#AV:A/AC:L/Au:N/C:N/I:P/A:P
Severity: Medium
Base Score: 5.4
Vector: CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L