CVE-2020-7942 — puppet
MEDIUMCVE-2020-7942 is a medium-severity (CVSS 6.5) CWE-295 vulnerability in puppet. A fix is available for puppet — see the affected versions and patch details below.
Improper Certificate Validation in Puppet
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2020-7942 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
puppet💎puppetReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Previously, Puppet operated on a 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 and 5.5.19 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. Affected software versions: Puppet 6.x prior to 6.13.0 Puppet Agent 6.x prior to 6.13.0 Puppet 5.5.x prior to 5.5.19 Puppet Agent 5.5.x prior to 5.5.19 Resolved in: Puppet 6.13.0 Puppet Agent 6.13.0 Puppet 5.5.19 Puppet Agent 5.5.19
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | puppet | ≥ 6.0.0&&< 6.13.0 | 6.13.0bundle update puppet --conservative |
| 💎RubyGems | puppet | all versions | 5.5.19bundle update puppet --conservative |
Affected Products
puppetpuppetpuppet agentpuppetDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for puppet, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update puppet to 6.13.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-7942 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
In Red Hat OpenStack Platform, Puppet is invoked as a standalone component (puppet master is not run). This means that although the vulnerable code might be present, it is not used, resulting in a lowered impact rating and no update will be provided at this time.
In the puppet.conf configuration file set `strict_hostname_checking = true`.Source: Red Hat security advisory for CVE-2020-7942 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Satellite 6.8 for RHEL 7 | ansible-collection-redhat-satellite-0:1.3.0-1.el7sat | RHSA-2020:4366 |
Frequently Asked Questions
Is CVE-2020-7942 in your dependencies?
Find it across RubyGems, including transitive dependencies.