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Big Ip Advanced Web Application FirewallApplication · F5

CVE-2021-23030

HIGH · 7.5 CVSS v3.1 Published 2021-09-14
Fix available
A fix is available. Upgrade to after 16.0.1.1 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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 BIG-IP Advanced WAF and BIG-IP ASM version 16.0.x before 16.0.1.2, 15.1.x before 15.1.3.1, 14.1.x before 14.1.4.3, 13.1.x before 13.1.4.1, and all versions of 12.1.x, when a WebSocket profile is configured on a virtual server, undisclosed requests can cause bd to terminate. 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 denial of service vulnerability in F5 BIG-IP Advanced WAF and ASM allows remote attackers to crash the bigd daemon by sending specially crafted WebSocket requests to virtual servers that have a WebSocket profile configured. The vulnerability affects multiple version branches including 12.1.x (all versions), 13.1.x before 13.1.4.1, 14.1.x before 14.1.4.3, 15.1.x before 15.1.3.1, and 16.0.x before 16.0.1.2.

MitigationUpgrade BIG-IP to the fixed versions (16.0.1.2+, 15.1.3.1+, 14.1.4.3+, 13.1.4.1+) or disable WebSocket profiles on affected virtual servers if upgrade is not immediately feasible.

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:>= 12.1.0, <= 12.1.6>= 13.1.0, <= 13.1.4>= 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:>= 12.1.0, <= 12.1.6>= 13.1.0, <= 13.1.4>= 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
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 the installed BIG-IP version
    Run command: tmsh show sys version or check the BIG-IP web UI under System > Software Management > ISO Image (shows installed version)
    Affected if The version falls within 12.1.0-12.1.6, 13.1.0-13.1.4, 14.1.0-14.1.4, 15.1.0-15.1.3, or 16.0.0-16.0.1.1
  2. Confirm the BIG-IP module is Advanced WAF or ASM
    Run command: tmsh list sys module or check the license information in the web UI under System > License
    Affected if The BIG-IP module license includes Application Security Manager (ASM) or Advanced WAF
  3. Check for configured WebSocket profiles
    Run command: tmsh list ltm profile websocket or inspect virtual servers via web UI under Local Traffic > Virtual Servers > Profiles
    Affected if Any WebSocket profile exists and is assigned to a virtual server
  4. Identify virtual servers using WebSocket profiles
    Run command: tmsh list ltm virtual all one-line | grep -i websocket or review virtual server configuration in the web UI
    Affected if A virtual server references a WebSocket profile

The system is vulnerable if it runs a affected BIG-IP version (12.1.x, 13.1.x before 13.1.4.1, 14.1.x before 14.1.4.3, 15.1.x before 15.1.3.1, or 16.0.x before 16.0.1.2) with ASM/Advanced WAF module and has a WebSocket profile assigned to any virtual server.

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 BIG-IP to the fixed versions (16.0.1.2+, 15.1.3.1+, 14.1.4.3+, 13.1.4.1+) or disable WebSocket profiles on affected virtual servers if upgrade is not immediately feasible.

Recommended fix High confidence

Upgrade to 16.0.1.2 (for 16.0.x), 15.1.3.1 (for 15.1.x), 14.1.4.3 (for 14.1.x), or 13.1.4.1 (for 13.1.x). Note: 12.1.x has no fix and is EoTS.

  1. Identify the current BIG-IP version by running 'tmsh show sys version' or checking the web UI
  2. Determine which BIG-IP product (Advanced WAF or ASM) is affected and which version branch (12.1.x, 13.1.x, 14.1.x, 15.1.x, or 16.0.x) is in use
  3. For 12.1.x versions: No fix available; this version is End of Technical Support (EoTS) and requires upgrade to a supported version
  4. For 16.0.x: Upgrade to version 16.0.1.2 or later
  5. For 15.1.x: Upgrade to version 15.1.3.1 or later
  6. For 14.1.x: Upgrade to version 14.1.4.3 or later
  7. For 13.1.x: Upgrade to version 13.1.4.1 or later
  8. Download the appropriate hotfix from support.f5.com after logging in with valid credentials
Caveat Upgrading across major version branches may require compatibility testing; review F5 release notes for any configuration or behavioral changes before upgrading.

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
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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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-2021-23030 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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