dbcve.org
RemediateApplication · Puppet

CVE-2021-27018

HIGH · 7.5 CVSS v3.1 Published 2021-08-30
Fix available
A fix is available. Upgrade to 2.0.1 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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
The mechanism which performs certificate validation was discovered to have a flaw that resulted in certificates signed by an internal certificate authority to not be properly validated. This issue only affects clients that are configured to utilize Tenable.sc as the vulnerability data source.

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 · moderate confidence

Tenable.sc contains a certificate validation flaw where certificates signed by an internal certificate authority are not properly validated. This allows potentially malicious certificates to be accepted, creating a man-in-the-middle attack vector. The vulnerability only manifests when Tenable.sc is used as the vulnerability data source.

MitigationEnsure Tenable.sc is updated to the latest version that addresses proper internal CA certificate validation. Verify certificate chain validation is functioning correctly in affected configurations.

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
RemediateApplication
Affected:< 2.0.1

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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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 Remediate installed version
    Run 'puppet-remediate --version' or check the package manager (e.g., 'rpm -q puppet-remediate' or 'dpkg -l puppet-remediate') to determine the installed version number
    Affected if The installed version is lower than 2.0.1 (e.g., 2.0.0, 1.x.x series)
  2. Verify Tenable.sc is configured as the vulnerability data source
    Inspect the Puppet Remediate configuration file (typically at /etc/puppet-remediate/remediate.conf or similar config directory) for a data source entry pointing to a Tenable.sc server
    Affected if The configuration shows Tenable.sc is set as the scanner or vulnerability data source (e.g., 'scanner_type=tenable_sc' or 'source=tenable.sc')
  3. Confirm internal CA certificate is in use
    Review the Tenable.sc connection settings in the Puppet Remediate configuration for custom CA certificate paths or inspect the Tenable.sc server itself for internally-signed certificates in the certificate chain
    Affected if The setup uses a private/internal Certificate Authority rather than a public CA for the Tenable.sc connection

You are affected if Puppet Remediate version is below 2.0.1 AND Tenable.sc is configured as the vulnerability data source, allowing internally-signed certificates to bypass proper validation.

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.

dbcve · scoped
Upgrade available Upgrade to 2.0.1 or later
Fixed in 2.0.1
Interim mitigation

Ensure Tenable.sc is updated to the latest version that addresses proper internal CA certificate validation. Verify certificate chain validation is functioning correctly in affected configurations.

Recommended fix High confidence

Remediate 2.0.1

  1. 1. Back up the current Puppet Remediate installation and configuration data
  2. 2. Download Puppet Remediate version 2.0.1 from the official Puppet download portal (puppet.com)
  3. 3. Install or upgrade to version 2.0.1 following the standard Puppet Remediate installation procedures
  4. 4. Verify the installation was successful by checking the Remediate version
  5. 5. If using Tenable.sc as the vulnerability data source, verify that certificate validation is now functioning correctly for internally-signed CA certificates

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Remediate Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

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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-2021-27018 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