Improper Certificate Validation in Puppet

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS

• CVE-2020-7942: 0.80% estimated exploitation activity in the next 30 days; percentile 56.66 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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 stricthostnamechecking = true in puppet.conf on your Puppet master. Puppet 6.13.0 changes the default behavior for stricthostnamechecking from false to true. It is recommended that Puppet Open Source and Puppet Enterprise users that are not upgrading still set stricthostnamechecking to true to ensure secure behavior.

Published by the source

13 Apr 2021, 15:42 UTC

Last modified by the source

5 Jul 2023, 19:26 UTC

Source last checked

26 Oct 2026, 15:47 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-gqvf-892r-vjm5

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# Patch Next advisory brief: CVE-2020-7942

Advisory: Improper Certificate Validation in Puppet
IDs: CVE-2020-7942, GHSA-gqvf-892r-vjm5
Record: https://patchnext.com/advisories/cve-2020-7942 (revision 1, source checked 26 Oct 2026, 15:47 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: puppet 6.13.0, 5.5.19. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems puppet: affected >= 6.0.0, < 6.13.0; < 5.5.19; fixed in 5.5.19, 6.13.0

## Suggested inspection (read-only)
- RubyGems puppet: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on puppet.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-gqvf-892r-vjm5 (GitHub-reviewed advisory GHSA-gqvf-892r-vjm5 lists affected ranges: RubyGems puppet >=6.0.0 =0 <5.5.19)

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