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Big Ip Access Policy ManagerApplication · F5

CVE-2021-23027

MEDIUM · 6.1 CVSS v3.1 Published 2021-09-14
Fix available
A fix is available. Upgrade to after 16.0.1.1 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 16.0.x before 16.0.1.2, 15.1.x before 15.1.3.1, and 14.1.x before 14.1.4.3, a DOM based 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 DOM-based cross-site scripting (XSS) vulnerability exists in the F5 BIG-IP Configuration utility affecting versions 16.0.x before 16.0.1.2, 15.1.x before 15.1.3.1, and 14.1.x before 14.1.4.3. The vulnerability allows an attacker to execute arbitrary JavaScript in the context of a logged-in user through an undisclosed page in the web-based configuration interface.

MitigationUpgrade to BIG-IP versions 16.0.1.2, 15.1.3.1, or 14.1.4.3 or later to remediate this vulnerability. Alternatively, apply the relevant F5 hotfix if available for supported versions.

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:>= 14.1.0, <= 14.1.4>= 15.1.0, <= 15.1.3>= 16.0.0, <= 16.0.1.1
Big Ip Advanced Firewall ManagerApplication
Affected:>= 14.1.0, <= 14.1.4>= 15.1.0, <= 15.1.3>= 16.0.0, <= 16.0.1.1
Big Ip Advanced Web Application FirewallApplication
Affected:>= 14.1.0, <= 14.1.4>= 15.1.0, <= 15.1.3>= 16.0.0, <= 16.0.1.1
Big Ip AnalyticsApplication
Affected:>= 14.1.0, <= 14.1.4>= 15.1.0, <= 15.1.3>= 16.0.0, <= 16.0.1.1
Big Ip Application Acceleration ManagerApplication
Affected:>= 14.1.0, <= 14.1.4>= 15.1.0, <= 15.1.3>= 16.0.0, <= 16.0.1.1
Big Ip Application Security ManagerApplication
Affected:>= 14.1.0, <= 14.1.4>= 15.1.0, <= 15.1.3>= 16.0.0, <= 16.0.1.1
Big Ip Ddos Hybrid DefenderApplication
Affected:>= 14.1.0, <= 14.1.4>= 15.1.0, <= 15.1.3>= 16.0.0, <= 16.0.1.1
Big Ip Domain Name SystemApplication
Affected:>= 14.1.0, <= 14.1.4>= 15.1.0, <= 15.1.3>= 16.0.0, <= 16.0.1.1

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. Check BIG-IP version via TMSH
    Run `tmsh show sys version` or `tmsh show sys hardware` and locate the BIG-IP version string in the output
    Affected if The version displayed falls within 14.1.0-14.1.4, 15.1.0-15.1.3, or 16.0.0-16.0.1.1
  2. Verify Configuration utility is accessible
    Attempt to reach the BIG-IP web GUI (usually port 443) or check via `tmsh list sys httpd` to see if the GUI is enabled
    Affected if The Configuration utility web interface is exposed and reachable on the network
  3. Confirm APM, ASM, AFM, or other affected module is licensed
    Run `tmsh list sys license` or check the System > License section in the GUI to see which modules are licensed
    Affected if Any of the affected modules (APM, AFM, AFM, AAM, ASM, DDoS Hybrid Defender, DNS) are licensed and active
  4. Check if user authentication to GUI is possible
    Review whether local or remote user accounts have access to the Configuration utility via `tmsh list auth user`
    Affected if User accounts exist that can authenticate to the Configuration utility, creating the attack vector context

You are affected if your BIG-IP version falls within 14.1.0 through 14.1.4, 15.1.0 through 15.1.3, or 16.0.0 through 16.0.1.1 AND the Configuration utility is accessible to authenticated users.

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 a release after 16.0.1.1
Interim mitigation

Upgrade to BIG-IP versions 16.0.1.2, 15.1.3.1, or 14.1.4.3 or later to remediate this vulnerability. Alternatively, apply the relevant F5 hotfix if available for supported versions.

Recommended fix High confidence

14.1.4.3 (for 14.1.x) or 15.1.3.1 (for 15.1.x) or 16.0.1.2 (for 16.0.x)

  1. 1. Identify the current BIG-IP version by running 'tmsh show sys version' or checking the Configuration utility login page.
  2. 2. Based on the current version, plan upgrade to the appropriate fixed release: 14.1.4.3 (for 14.1.x), 15.1.3.1 (for 15.1.x), or 16.0.1.2 (for 16.0.x).
  3. 3. Download the hotfix from F5 Networks support portal (support.f5.com) after authenticating with valid credentials.
  4. 4. Review F5 BIG-IP upgrade guide for the upgrade procedure applicable to your deployment mode (standalone, HA pair, or cluster).
  5. 5. Perform the upgrade during a planned maintenance window following F5 recommended upgrade procedures.

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
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,968.

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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-2021-23027 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