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Big Ip Access Policy ManagerApplication · F5

CVE-2021-23054

MEDIUM · 6.1 CVSS v3.1 Published 2021-09-27
Fix available
A fix is available. Upgrade to 14.1.4.4 / 15.1.4 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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.x before 16.1.0, 15.1.x before 15.1.4, 14.1.x before 14.1.4.4, and all versions of 13.1.x, 12.1.x, and 11.6.x, a reflected cross-site scripting (XSS) vulnerability exists in the resource information page for authenticated users when a full webtop is configured on the BIG-IP APM system. 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 reflected cross-site scripting (XSS) vulnerability exists in the F5 BIG-IP APM system's resource information page when a full webtop is configured. Authenticated users can inject malicious scripts through unsanitized input that gets reflected back and executed in their browser session.

MitigationUpgrade BIG-IP APM to version 16.1.0 or later, 15.1.4 or later, or 14.1.4.4 or later. Alternatively, implement input validation and output encoding on the affected webtop resource information endpoint.

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:>= 11.6.1, <= 11.6.5>= 12.1.0, <= 12.1.6>= 13.1.0, <= 13.1.4>= 14.1.0, < 14.1.4.4>= 15.1.0, < 15.1.4>= 16.0.0, < 16.0.1

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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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. Verify BIG-IP APM is installed
    Log into the BIG-IP command line and run `tmsh show /sys module` or check the installed modules to confirm the Access Policy Manager (APM) module is present.
    Affected if APM module is not installed, the system is not affected by this specific vulnerability.
  2. Check APM version against affected ranges
    Run `tmsh show /sys version` or use the web management console to view the BIG-IP version. Compare the installed APM version to the affected ranges: 11.6.1-11.6.5, 12.1.0-12.1.6, 13.1.0-13.1.4, 14.1.0-14.1.4.3, 15.1.0-15.1.3, or 16.0.0-16.0.0.x.
    Affected if The installed version falls within any of the listed affected version ranges.
  3. Confirm full webtop configuration exists
    Access the BIG-IP web management console, navigate to Access Policy > Webtops, or use the equivalent tmsh command to list configured webtops. Identify whether any webtop is configured with the 'full' type rather than 'lite' or other types.
    Affected if A full webtop resource is configured in the APM policy. The vulnerability only applies when a full webtop is in use.
  4. Inspect resource information page for unsanitized parameters
    As an authenticated APM user with webtop access, navigate to the resource information page within the full webtop interface. Examine URL parameters for any user-supplied input that gets reflected back in the response without encoding.
    Affected if URL parameters in the resource information page reflect user input without proper HTML encoding, allowing script injection.

The environment is affected if BIG-IP APM is installed with a version in the affected ranges AND a full webtop is configured, exposing the resource information page to reflected XSS.

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 14.1.4.4 / 15.1.4 / 16.0.1 or later
Fixed in 14.1.4.415.1.416.0.1
Interim mitigation

Upgrade BIG-IP APM to version 16.1.0 or later, 15.1.4 or later, or 14.1.4.4 or later. Alternatively, implement input validation and output encoding on the affected webtop resource information endpoint.

Recommended fix High confidence

Upgrade to 14.1.4.4+ (if on 14.1.x), 15.1.4+ (if on 15.1.x), or 16.1.0+ (if on 16.x). For 11.6.x, 12.1.x, and 13.1.x branches, upgrade to the next stable branch that has a fix.

  1. Identify the current BIG-IP APM version using 'tmsh show sys version' or the web management console
  2. Determine the appropriate upgrade path based on current version (11.6.x, 12.1.x, 13.1.x, or 14.1.x)
  3. Review F5 upgrade guides and release notes for the target version to ensure compatibility
  4. Back up the current configuration using 'tmsh save sys config'
  5. Upgrade to the fixed version: 14.1.4.4 or later, 15.1.4 or later, or 16.1.0 or later
  6. After upgrade, verify the APM module is functioning correctly
  7. Confirm the fix by checking that the resource information page no longer reflects unsanitized input
Caveat Major version upgrades may introduce breaking changes; review F5 release notes for deprecation notices and configuration changes before upgrading

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
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2021-23054 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