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Big Ip Advanced Web Application FirewallApplication · F5

CVE-2021-23031

CRITICAL · 9.9 CVSS v3.1 Published 2021-09-14
Fix available
A fix is available. Upgrade to after 16.0.1.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable 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
On version 16.0.x before 16.0.1.2, 15.1.x before 15.1.3, 14.1.x before 14.1.4.1, 13.1.x before 13.1.4, 12.1.x before 12.1.6, and 11.6.x before 11.6.5.3, an authenticated user may perform a privilege escalation on the BIG-IP Advanced WAF and ASM Configuration utility. 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 · moderate confidence

This is an authenticated privilege escalation vulnerability in the BIG-IP Advanced WAF and ASM Configuration utility affecting multiple version branches (16.x, 15.x, 14.x, 13.x, 12.x, 11.x). An authenticated user with access to the configuration utility can elevate their privileges, likely gaining administrative or higher-level access within the WAF/ASM system.

MitigationApply the appropriate F5 patch: upgrade to 16.0.1.2+, 15.1.3+, 14.1.4.1+, 13.1.4+, 12.1.6+, or 11.6.5.3+ depending on the deployed version branch.

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 Advanced Web Application FirewallApplication
Affected:>= 11.6.1, <= 11.6.5.2>= 12.1.0, <= 12.1.5>= 13.1.0, <= 13.1.3>= 14.1.0, <= 14.1.4>= 15.1.0, <= 15.1.2>= 16.0.0, <= 16.0.1.1
Big Ip Application Security ManagerApplication
Affected:>= 11.6.1, <= 11.6.5.2>= 12.1.0, <= 12.1.5>= 13.1.0, <= 13.1.3>= 14.1.0, <= 14.1.4>= 15.1.0, <= 15.1.2>= 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
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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 installed F5 product
    Run 'tmsh show sys version' or check /var/log/boot.log for F5 BIG-IP initialization messages, or inspect /etc/product_version if accessible
    Affected if Neither BIG-IP Advanced WAF nor ASM is installed
  2. Check BIG-IP version
    Run 'tmsh show sys version' or access the Configuration utility and navigate to System > Software Management > ISO Image (version displayed in GUI)
    Affected if Installed version falls within 11.6.1-11.6.5.2, 12.1.0-12.1.5, 13.1.0-13.1.3, 14.1.0-14.1.4, 15.1.0-15.1.2, or 16.0.0-16.0.1.1
  3. Verify Configuration utility accessibility
    Check if the BIG-IP Configuration utility (GUI on port 443) is exposed to network by reviewing tmsh output 'tmsh list sys httpd' or checking access profiles
    Affected if Configuration utility is network-accessible and accepts authenticated connections
  4. Confirm user access to Configuration utility
    Review user accounts in the Configuration utility under User Management > User List or via 'tmsh list auth user'
    Affected if Any non-administrator user accounts exist with Configuration utility access

Environment is affected if BIG-IP Advanced WAF or ASM is installed, version is within the listed ranges, 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

Apply the appropriate F5 patch: upgrade to 16.0.1.2+, 15.1.3+, 14.1.4.1+, 13.1.4+, 12.1.6+, or 11.6.5.3+ depending on the deployed version branch.

Recommended fix High confidence

Upgrade to one of: 11.6.5.3+, 12.1.6+, 13.1.4+, 14.1.4.1+, 15.1.3+, or 16.0.1.2+ (choose the appropriate branch matching your current major version)

  1. 1. Identify the current Big-IP version by running 'tmsh show sys version' or checking the web UI (System > Software > Image List)
  2. 2. Backup the current configuration using 'tmsh save sys config' or via the web UI (System > Archives > Create)
  3. 3. Download the appropriate fixed version from the F5 downloads portal (support.f5.com): For 11.6.x upgrade to 11.6.5.3+ (if still supported), For 12.1.x upgrade to 12.1.6+, For 13.1.x upgrade to 13.1.4+, For 14.1.x upgrade to 14.1.4.1+, For 15.1.x upgrade to 15.1.3+, For 16.0.x upgrade to 16.0.1.2+
  4. 4. Upload the ISO image to the Big-IP via web UI (System > Software > Upload) or SCP
  5. 5. Create a new boot location: tmsh install sys software volume <volume_name> image <image_name>
  6. 6. Reboot into the new volume: tmsh boot system volume <volume_name>
  7. 7. Verify the upgrade was successful and the vulnerability is resolved by checking the installed version
Caveat F5 recommends testing the upgrade in a staging environment first as configuration changes between major versions may affect behavior; also note 11.6.x has reached End of Technical Support and may require more complex migration to a newer major version

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

Fix this in Big Ip Advanced Web Application Firewall Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2021-23031 in production — separate from our analysis above.

No notes yet

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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
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  • Version or environment caveats, and links to real fixes
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