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CRITICAL severity

CVE-2021-27023 — puppet

CRITICAL

CVE-2021-27023 is a critical-severity (CVSS 9.8) vulnerability in puppet. A fix is available for puppet — see the affected versions and patch details below.

Unsafe HTTP Redirect in Puppet Agent and Puppet Server

Also known asGHSA-93j5-g845-9wqp
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Oct 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.4%probability of exploitation in next 30 days
Lower Risk+0.04%
Lower risk than most CVEs71th percentile — riskier than 71% of all scored CVEsHighest risk
0.00%0.62%1.25%1.87%0.4%1.4%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-27023 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

2 pkgs affected
💎puppet💎puppet

Real-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

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

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemspuppet≥ 7.0.0&&< 7.12.17.12.1bundle update puppet --conservative
💎RubyGemspuppetall versions6.25.1bundle update puppet --conservative

Affected Products

4 products · 7 configurations
OS
fedorafedoraproject
1 version
35
Application
puppet agentpuppet
≥ 7.0.0 && < 7.12.1
range
Application
puppet enterprisepuppet
≥ 2021.0.0 && < 2021.4
range
Application
puppet serverpuppet
≥ 7.0.0 && < 7.4.2
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    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.

  2. Fix

    Update puppet to 7.12.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-27023 is resolved across your whole dependency graph.

  3. 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.

Red HatImportant

Red Hat Satellite 6.8 and earlier versions are not affected by this vulnerability.

ProductFixed inAdvisory
Red Hat Satellite 6.10 for RHEL 7puppet-agent-0:6.26.0-1.el7satRHSA-2022:1708
Red Hat Satellite 6.9 for RHEL 7puppet-agent-0:6.26.0-1.el7satRHSA-2022:1478
Satellite Tools 6.10 for RHEL 6.ELSpuppet-agent-0:6.26.0-1.el6satRHSA-2022:4866
Satellite Tools 6.9 for RHEL 6.ELSpuppet-agent-0:6.26.0-1.el6satRHSA-2022:4867

Frequently Asked Questions

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
O3 Security · Impact-Aware SCA

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CVE-2021-27023: puppet — Fixed in 7.12.1