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Ansible Automation PlatformApplication · Redhat

CVE-2021-3583

HIGH · 7.1 CVSS v3.1 Published 2021-09-22
Fix available
A fix is available. Upgrade to 2.9.23 / 3.7.0 or later.
See remediation →
73/100
Remediation priority · Elevated
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 found in Ansible, where a user's controller is vulnerable to template injection. This issue can occur through facts used in the template if the user is trying to put templates in multi-line YAML strings and the facts being handled do not routinely include special template characters. This flaw allows attackers to perform command injection, which discloses sensitive information. The highest threat from this vulnerability is to confidentiality and integrity.

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

A template injection vulnerability exists in Ansible where facts containing special template characters can execute arbitrary commands when used in multi-line YAML strings. An attacker who controls fact data or can influence what facts are collected can inject commands that execute on the Ansible controller, exposing sensitive information.

MitigationUpgrade Ansible to the patched version. Additionally, audit playbooks for multi-line YAML template usage and implement input validation/sanitization on facts before using them in Jinja2 templates.

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
Ansible Automation PlatformApplication
Affected:= 1.2
Ansible EngineApplication
Affected:< 2.9.23
Ansible TowerApplication
Affected:< 3.7.0

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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 Ansible version
    Run 'ansible --version' or 'ansible-playbook --version' to see the installed version
    Affected if Version is Ansible Engine < 2.9.23, Ansible Tower < 3.7.0, or Ansible Automation Platform = 1.2
  2. Identify multi-line YAML template usage
    Search playbooks for '| from_yaml' or '| from_yaml_all' filters applied to variables or facts, especially in multi-line YAML string contexts (| or >)
    Affected if Playbooks contain multi-line YAML template filters processing fact data without sanitization
  3. Review custom and gathered facts
    Inspect /etc/ansible/facts.d/ or custom fact paths for any fact data that could contain user-controlled content or special Jinja2 template characters
    Affected if Custom facts can be influenced by untrusted users or contain unsanitized template syntax

You are affected if running a vulnerable Ansible version AND using facts in multi-line YAML template contexts like | from_yaml filters without input 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 2.9.23 / 3.7.0 or later
Fixed in 2.9.233.7.0
Interim mitigation

Upgrade Ansible to the patched version. Additionally, audit playbooks for multi-line YAML template usage and implement input validation/sanitization on facts before using them in Jinja2 templates.

Recommended fix High confidence

Ansible Engine: 2.9.23+ | Ansible Tower: 3.7.0+ | Ansible Automation Platform: 1.2.1+

  1. 1. Identify the current Ansible Engine, Tower, or Automation Platform version in use by checking the package manager or tower-cli version command
  2. 2. For Ansible Engine: Upgrade to version 2.9.23 or later using the appropriate package manager (e.g., `pip install --upgrade ansible==2.9.23` or your system package manager)
  3. 3. For Ansible Tower: Upgrade to version 3.7.0 or later following the standard Tower upgrade procedure documented in the official Red Hat Ansible Tower upgrade guide
  4. 4. For Ansible Automation Platform: Upgrade to version 1.2.1 or later following the AAP upgrade documentation
  5. 5. After upgrade, verify the Ansible version with `ansible --version` to confirm the patch was applied
  6. 6. Test critical playbooks to ensure functionality is maintained after the upgrade
Caveat Review Ansible release notes for 2.9.23 and 3.7.0 for any behavior changes that may affect existing playbooks; minor version upgrades typically maintain backward compatibility

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

Fix this in Ansible Automation Platform Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing8.0 h
  • Review / QA4.0 h
18.0 hours of engineering $3,080
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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-2021-3583 in production — separate from our analysis above.

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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