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FedoraOperating system · Fedoraproject

CVE-2021-27023

CRITICAL · 9.8 CVSS v3.1 Published 2021-11-18
Fix available
A fix is available. Upgrade to 6.17.1 / 6.25.1 or later.
See remediation →
100/100
Remediation priority · Urgent
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
A flaw was discovered in Puppet Agent and Puppet Server that may result in a leak of HTTP credentials when following HTTP redirects to a different host. This is similar to CVE-2018-1000007

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

A flaw in Puppet Agent and Puppet Server allows HTTP credentials to leak when the client follows HTTP redirects to a different host. When a user authenticates to an initial server that returns a redirect response, the credentials may be transmitted to the redirected (different) host, similar to the curl vulnerability CVE-2018-1000007.

MitigationApply vendor patches for Puppet Agent and Puppet Server when available. In the interim, avoid using HTTP endpoints that may redirect to untrusted hosts and ensure credentials are only sent over TLS with proper host verification.

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
FedoraOperating system
Affected:= 35
Puppet AgentApplication
Affected:< 6.25.1>= 7.0.0, < 7.12.1
Puppet EnterpriseApplication
Affected:< 2019.8.9>= 2021.0.0, < 2021.4
Puppet ServerApplication
Affected:< 6.17.1>= 7.0.0, < 7.4.2

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
High
Integrity
High
Availability
High

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

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. Identify Puppet Agent version
    Run `puppet --version` or check the installed package version via your system package manager (e.g., `rpm -q puppet-agent` or `dpkg -l puppet-agent`)
    Affected if Version is < 6.25.1, or >= 7.0.0 and < 7.12.1
  2. Identify Puppet Server version
    Run `puppetserver --version` or check the installed package version via your system package manager (e.g., `rpm -q puppetserver` or `dpkg -l puppetserver`)
    Affected if Version is < 6.17.1, or >= 7.0.0 and < 7.4.2
  3. Identify Puppet Enterprise version
    Check the Puppet Enterprise version via `puppet-enterprise-version` command or inspect installed packages
    Affected if Version is < 2019.8.9, or >= 2021.0.0 and < 2021.4
  4. Check if Puppet uses HTTP instead of HTTPS
    Inspect Puppet configuration files (typically in `/etc/puppetlabs/puppet/puppet.conf` or `/etc/puppet/puppet.conf`) and look for `server=` settings that use `http://` rather than `https://`, or check environment variables and code that configures Puppet communications
    Affected if Puppet communications are configured to use unencrypted HTTP URLs where credentials may be transmitted
  5. Check if authentication credentials are configured
    Review Puppet configuration for `authconfig`, `clientcert`, `clientpwd`, or other credential-related settings in the puppet.conf file, or check for use of `http` scheme in any custom authentication configurations
    Affected if Authentication credentials are configured and could be sent along with HTTP redirects

You are affected if you have an affected Puppet Agent, Server, or Enterprise version AND use HTTP (unencrypted) connections with authentication credentials that could be redirected to a different host.

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 6.17.1 / 6.25.1 / 7.4.2 or later
Fixed in 6.17.16.25.17.4.2
Interim mitigation

Apply vendor patches for Puppet Agent and Puppet Server when available. In the interim, avoid using HTTP endpoints that may redirect to untrusted hosts and ensure credentials are only sent over TLS with proper host verification.

Recommended fix High confidence

Puppet Agent: upgrade to >= 6.25.1 or >= 7.12.1; Puppet Server: upgrade to >= 6.17.1 or >= 7.4.2; Puppet Enterprise: upgrade to >= 2019.8.9 or >= 2021.4

  1. Identify the Puppet product in use (Agent, Server, or Enterprise) and current version by checking the installed package or running 'puppet --version'
  2. For Puppet Agent: If using version 6.x, upgrade to 6.25.1 or later; if using version 7.x, upgrade to 7.12.1 or later
  3. For Puppet Server: If using version 6.x, upgrade to 6.17.1 or later; if using version 7.x, upgrade to 7.4.2 or later
  4. For Puppet Enterprise: If using version 2019.x, upgrade to 2019.8.9 or later; if using version 2021.x, upgrade to 2021.4 or later
  5. Back up all Puppet configuration files, manifests, and Hiera data before upgrading
  6. Use the appropriate package manager (yum, dnf, or apt) or Puppet's official installer to apply the upgrade
  7. Restart Puppet services (puppetserver, puppet) after the upgrade completes
  8. Verify the upgrade was successful by checking the new version and testing basic agent runs
Caveat Review Puppet release notes for your specific version jump to check for any deprecated features or configuration changes that may affect your setup

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

Fix this in Fedora Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2021-27023 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