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Ansible TowerApplication · Redhat

CVE-2021-20253

MEDIUM · 6.7 CVSS v3.1 Published 2021-03-09
Fix available
A fix is available. Upgrade to 3.6.7 / 3.7.5 or later.
See remediation →
67/100
Remediation priority · Elevated

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-tower. The default installation is vulnerable to Job Isolation escape allowing an attacker to elevate the privilege from a low privileged user to the awx user from outside the isolated environment. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

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

Ansible Tower's default installation contains a Job Isolation escape vulnerability. Low-privileged users can escape the isolated containerized job execution environment and escalate privileges to the awx system user from outside the isolated environment, compromising the containment boundaries designed to protect the Tower host.

MitigationReview and properly configure Job Isolation settings in Ansible Tower/AWX to ensure proper containerization and sandboxing of job execution. Verify that the isolation mechanism correctly prevents escape to the host system.

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 TowerApplication
Affected:< 3.6.7>= 3.7.0, < 3.7.5>= 3.8.0, < 3.8.2

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
Local
Complexity
High
Privileges
Low
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/UI:R/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 installed Ansible Tower version
    Access the Tower UI as an admin and navigate to Settings > About, or use the API endpoint /api/v2/config/ to retrieve the version information. Alternatively, check the installation manifest or RPM package if you have CLI access.
    Affected if The version falls below 3.6.7, is between 3.7.0-3.7.4, or is between 3.8.0-3.8.1 (meaning it is one of the affected versions listed).
  2. Confirm Job Isolation feature is enabled
    Navigate to Settings > Jobs in the Tower UI and locate the 'Job Isolation' setting. Check whether the isolation mechanism is turned on. In the API, query /api/v2/settings/jobs/ and look for the 'ISOLATION' or job isolation related parameters.
    Affected if Job Isolation is enabled and the Tower version is one of the vulnerable versions listed.
  3. Verify containerized job execution settings
    In the Tower UI under Settings > Jobs, examine the 'Container Registry' and 'Job Execution' environment settings. Check if jobs are configured to run inside isolated containers. Review the /api/v2/settings/ jobs/ endpoint for isolation-related configuration keys.
    Affected if Containerized job execution is active and the version is within the affected range.
  4. Review execution environment configuration
    Check the defined Execution Environments in Tower under Resources > Execution Environments. Determine if the default execution environment is being used and whether it includes the isolation wrapper. Inspect the awx-manage dump_survey_passwords or related management commands if accessible.
    Affected if Default execution environments are in use and the Tower version is vulnerable.

You are affected if your installed Ansible Tower version matches one of the vulnerable ranges (below 3.6.7, 3.7.0-3.7.4, or 3.8.0-3.8.1) AND the Job Isolation feature is enabled for job execution.

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 3.6.7 / 3.7.5 / 3.8.2 or later
Fixed in 3.6.73.7.53.8.2
Interim mitigation

Review and properly configure Job Isolation settings in Ansible Tower/AWX to ensure proper containerization and sandboxing of job execution. Verify that the isolation mechanism correctly prevents escape to the host system.

Fix this in Ansible Tower Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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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-2021-20253 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
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