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PuppetApplication

CVE-2020-7942

MEDIUM · 6.5 CVSS v3.1 Published 2020-02-19
Fix available
A fix is available. Upgrade to 5.5.19 / 6.13.0 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Puppet's authentication model allowed a node with a valid certificate to retrieve catalogs for different nodes by modifying facts when the catalog falls back to the 'default' node. This enables unauthorized access to configuration data intended for other nodes.

MitigationSet `strict_hostname_checking = true` in puppet.conf on all Puppet masters, or upgrade to Puppet 6.13.0+ / 5.5.19+ which changes the default to true.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
PuppetApplication
Affected:>= 5.5.0, < 5.5.19>= 6.0.0, < 6.13.0
Puppet AgentApplication
Affected:>= 5.5.0, < 5.5.19>= 6.0.0, < 6.13.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Puppet Server version
    Run `puppet --version` on the Puppet master server to determine the installed version
    Affected if The version is >= 5.5.0 and < 5.5.19, or >= 6.0.0 and < 6.13.0
  2. Check Puppet Agent version
    Run `puppet --version` on the Puppet agent nodes to determine the installed version
    Affected if The version is >= 5.5.0 and < 5.5.19, or >= 6.0.0 and < 6.13.0
  3. Locate puppet.conf
    Find the puppet.conf configuration file, typically at /etc/puppet/puppet.conf or /etc/puppetserver/puppetserver.conf on the Puppet master
    Affected if File exists on an affected version
  4. Check strict_hostname_checking setting
    Inspect puppet.conf for the `strict_hostname_checking` setting in the [master] section. Look for `strict_hostname_checking = true` or `strict_hostname_checking = false`, or if the setting is absent (default)
    Affected if The setting is absent or set to false on an affected version (the vulnerability allows unauthorized catalog access when this is not set to true)

A node is affected if running Puppet version 5.5.0-5.5.18 or 6.0.0-6.12.0 AND strict_hostname_checking is not set to true in puppet.conf on the Puppet master.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 5.5.19 / 6.13.0 or later
Fixed in 5.5.196.13.0
Interim mitigation

Set `strict_hostname_checking = true` in puppet.conf on all Puppet masters, or upgrade to Puppet 6.13.0+ / 5.5.19+ which changes the default to true.

Fix this in Puppet Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,570
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-7942 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data