Previously, Puppet operated on the model that a node with a valid certificate was entitled to all information in the system and that a compromised certificate allowed access to everything in the infrastructure. When a node's catalog falls back to the default node, the catalog can be retrieved for a different node by modifying facts for the Puppet run. This issue can be mitigated by setting strict_hostname_checking = true in puppet.conf on your Puppet master. Puppet 6.13.0 changes the default behavior for strict_hostname_checking from false to true. It is recommended that Puppet Open Source and Puppet Enterprise users that are not upgrading still set strict_hostname_checking to true to ensure secure behavior.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-7942
• https://puppet.com/security/cve/CVE-2020-7942/
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/puppet/CVE-2020-7942.yml