Summary
Improper Certificate Validation in Puppet
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.
Impact
CVE-2020-7942 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (6.13.0, 5.5.19); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
puppet to 6.13.0 or later; puppet to 5.5.19 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2020-7942? CVE-2020-7942 is a medium-severity security vulnerability in puppet (rubygems), affecting versions >= 6.0.0, < 6.13.0. It is fixed in 6.13.0, 5.5.19.
- How severe is CVE-2020-7942? CVE-2020-7942 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of puppet are affected by CVE-2020-7942? puppet (rubygems) versions >= 6.0.0, < 6.13.0 is affected.
- Is there a fix for CVE-2020-7942? Yes. CVE-2020-7942 is fixed in 6.13.0, 5.5.19. Upgrade to this version or later.
- Is CVE-2020-7942 exploitable, and should I be worried? Whether CVE-2020-7942 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2020-7942 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2020-7942?
- Upgrade
puppetto 6.13.0 or later - Upgrade
puppetto 5.5.19 or later
- Upgrade