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Big Ip Access Policy ManagerApplication · F5

CVE-2021-23038

CRITICAL · 9.0 CVSS v3.1 Published 2021-09-14
Fix available
A fix is available. Upgrade to 13.1.4.1 / 14.1.4.2 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable

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
On version 16.0.x before 16.0.1.2, 15.1.x before 15.1.3.1, 14.1.x before 14.1.4.2, 13.1.x before 13.1.4.1, and all versions of 12.1.x, a stored cross-site scripting (XSS) vulnerability exists in an undisclosed page of the BIG-IP Configuration utility that allows an attacker to execute JavaScript in the context of the currently logged-in user. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

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 stored cross-site scripting (XSS) vulnerability exists in the F5 BIG-IP Configuration utility affecting multiple version branches. An attacker can inject malicious JavaScript code into an undisclosed page of the configuration utility, which persists and executes in the context of any user who views the affected content, allowing session hijacking or administrative actions.

MitigationUpgrade BIG-IP to version 16.0.1.2 or later, 15.1.3.1 or later, 14.1.4.2 or later, or 13.1.4.1 or later. Versions 12.1.x are end-of-life with no patch available; migrate to a supported version.

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
Big Ip Access Policy ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.2>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Advanced Firewall ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.2>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip AnalyticsApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.2>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Application Acceleration ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.2>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Application Security ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.2>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Domain Name SystemApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.2>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Fraud Protection ServiceApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.2>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Global Traffic ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.2>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2

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
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/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 BIG-IP installation and version
    Run `tmsh show sys version` or `bigpipe version` on the command line to obtain the installed BIG-IP version.
    Affected if The version matches any of the affected ranges: 12.1.0-12.1.6, 13.1.0-13.1.4.0, 14.1.0-14.1.4.1, 15.1.0-15.1.3.0, or 16.0.0-16.0.1.1.
  2. Confirm enabled modules
    Run `tmsh list sys module` or check the GUI under System > Software Management > Microkernel/Big-IP Module for installed modules.
    Affected if Any of these modules are enabled: Access Policy Manager, Advanced Firewall Manager, Analytics, Application Acceleration Manager, Application Security Manager, Domain Name System, Fraud Protection Service, or Global Traffic Manager.
  3. Check Configuration utility status
    Verify the BIG-IP Configuration utility (web GUI) is accessible by attempting to reach https://<management-ip>/tmui/ or checking service status with `tmsh list sys httpd`.
    Affected if The Configuration utility is enabled and accessible.
  4. Verify vulnerable version against patch releases
    Compare your exact version number to the fixed releases: 13.1.4.1 or later, 14.1.4.2 or later, 15.1.3.1 or later, 16.0.1.2 or later. Note that 12.1.x versions have no patch.
    Affected if Your installed version is lower than any of the fixed version numbers listed and you are on a 12.1.x through 16.0.1.1 range.

You are affected if your BIG-IP version falls within the listed ranges, any of the affected modules are enabled, and the Configuration utility is accessible.

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 13.1.4.1 / 14.1.4.2 / 15.1.3.1 or later
Fixed in 13.1.4.114.1.4.215.1.3.1
Interim mitigation

Upgrade BIG-IP to version 16.0.1.2 or later, 15.1.3.1 or later, 14.1.4.2 or later, or 13.1.4.1 or later. Versions 12.1.x are end-of-life with no patch available; migrate to a supported version.

Recommended fix High confidence

Upgrade to 16.0.1.2, 15.1.3.1, 14.1.4.2, or 13.1.4.1 (depending on your current major version branch); 12.1.x has no fix as it is End of Technical Support

  1. Identify the current BIG-IP version by running 'tmsh show sys version' or checking the Configuration utility login page
  2. Determine which BIG-IP module (APM, AFM, Analytics, AAM, ASM, DNS, FPS, or GTM) is affected in your deployment
  3. Plan the upgrade considering your current version: for 12.1.x versions (End of Technical Support), migrate to a supported version; for 13.1.x, upgrade to 13.1.4.1 or later; for 14.1.x, upgrade to 14.1.4.2 or later; for 15.1.x, upgrade to 15.1.3.1 or later; for 16.0.x, upgrade to 16.0.1.2 or later
  4. Review F5 upgrade documentation and release notes for the target version to understand prerequisites and procedures
  5. Perform a backup of the BIG-IP configuration before upgrading
  6. Execute the upgrade following F5's recommended upgrade procedure (typically via ISO image or Hotfix)
  7. After upgrade, verify the Configuration utility is accessible and the undisclosed page no longer contains the XSS vulnerability
  8. Confirm the new version is running with 'tmsh show sys version'
Caveat BIG-IP 12.1.x has reached End of Technical Support with no patch available - migration to a newer version is required; review F5 release notes for any configuration or behavioral changes in the target version

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

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation6.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,260
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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-2021-23038 in production — separate from our analysis above.

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What this is

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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