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Big Ip Access Policy ManagerApplication · F5

CVE-2021-23004

HIGH · 7.5 CVSS v3.1 Published 2021-03-31
Fix available
A fix is available. Upgrade to 11.6.5.3 / 12.1.5.3 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 versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2, 14.1.x before 14.1.3.1, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3, and 11.6.x before 11.6.5.3, Multipath TCP (MPTCP) forwarding flows may be created on standard virtual servers without MPTCP enabled in the applied TCP profile. Note: Software versions which have reached End of Software Development (EoSD) 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

On affected BIG-IP versions, Multipath TCP (MPTCP) forwarding flows can be created on standard virtual servers even when MPTCP is not enabled in the applied TCP profile. This represents a logic flaw where the MPTCP flow handling does not properly respect the TCP profile configuration, potentially allowing unexpected MPTCP behavior on virtual servers that administrators believe have MPTCP disabled.

MitigationUpgrade BIG-IP to version 16.0.1.1, 15.1.2, 14.1.3.1, 13.1.3.6, 12.1.5.3, or 11.6.5.3 or later. If upgrading is not immediately possible, review virtual server configurations and consider disabling MPTCP at the global level if not required.

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, < 11.6.5.3>= 12.1.0, < 12.1.5.3>= 13.1.0, < 13.1.3.6>= 14.1.0, < 14.1.4>= 15.1.0, < 15.1.2.1>= 16.0.0, < 16.0.1.1
Big Ip Advanced Firewall ManagerApplication
Affected:>= 11.6.1, < 11.6.5.3>= 12.1.0, < 12.1.5.3>= 13.1.0, < 13.1.3.6>= 14.1.0, < 14.1.4>= 15.1.0, < 15.1.2.1>= 16.0.0, < 16.0.1.1
Big Ip Advanced Web Application FirewallApplication
Affected:>= 11.6.1, < 11.6.5.3>= 12.1.0, < 12.1.5.3>= 13.1.0, < 13.1.3.6>= 14.1.0, < 14.1.4>= 15.1.0, < 15.1.2.1>= 16.0.0, < 16.0.1.1
Big Ip AnalyticsApplication
Affected:>= 11.6.1, < 11.6.5.3>= 12.1.0, < 12.1.5.3>= 13.1.0, < 13.1.3.6>= 14.1.0, < 14.1.4>= 15.1.0, < 15.1.2.1>= 16.0.0, < 16.0.1.1
Big Ip Application Acceleration ManagerApplication
Affected:>= 11.6.1, < 11.6.5.3>= 12.1.0, < 12.1.5.3>= 13.1.0, < 13.1.3.6>= 14.1.0, < 14.1.4>= 15.1.0, < 15.1.2.1>= 16.0.0, < 16.0.1.1
Big Ip Application Security ManagerApplication
Affected:>= 11.6.1, < 11.6.5.3>= 12.1.0, < 12.1.5.3>= 13.1.0, < 13.1.3.6>= 14.1.0, < 14.1.4>= 15.1.0, < 15.1.2.1>= 16.0.0, < 16.0.1.1
Big Ip Ddos Hybrid DefenderApplication
Affected:>= 11.6.1, < 11.6.5.3>= 12.1.0, < 12.1.5.3>= 13.1.0, < 13.1.3.6>= 14.1.0, < 14.1.4>= 15.1.0, < 15.1.2.1>= 16.0.0, < 16.0.1.1
Big Ip Domain Name SystemApplication
Affected:>= 11.6.1, < 11.6.5.3>= 12.1.0, < 12.1.5.3>= 13.1.0, < 13.1.3.6>= 14.1.0, < 14.1.4>= 15.1.0, < 15.1.2.1>= 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. Determine the installed BIG-IP version
    Run 'tmsh show sys version' or check the web UI under Dashboard > Overview > System > Software Version
    Affected if The version falls within any of these ranges: 11.6.1 to 11.6.5.2, 12.1.0 to 12.1.5.2, 13.1.0 to 13.1.3.5, 14.1.0 to 14.1.3, 15.1.0 to 15.1.2.0, or 16.0.0 to 16.0.1.0
  2. Identify virtual servers using standard profiles
    Run 'tmsh list ltm virtual' and examine the 'profile' or 'profiles' section of each virtual server configuration
    Affected if Any standard virtual server exists on the affected device regardless of TCP profile settings
  3. Verify MPTCP configuration in TCP profiles
    Run 'tmsh list ltm tcp' to list all TCP profiles, then for each profile run 'tmsh list ltm tcp <profile_name>' and check the 'mptcp' setting
    Affected if MPTCP is set to 'enabled' or 'allow' in any TCP profile applied to virtual servers, or if MPTCP is enabled at the global level via 'tmsh list sys db tcp.mptcp'
  4. Check for existing MPTCP forwarding flows
    Run 'tmsh show ltm flow' or 'tmsh show ltm mptcp connection' to see active MPTCP flows on the device
    Affected if Any MPTCP flows exist on virtual servers where administrators believe MPTCP is disabled in the applied TCP profile

You are affected if your BIG-IP version is within the affected ranges listed and you have virtual servers with TCP profiles, regardless of whether MPTCP appears disabled in those profiles, because the logic flaw allows MPTCP flows to be created unexpectedly.

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.

From vendor data
Upgrade available Upgrade to 11.6.5.3 / 12.1.5.3 / 13.1.3.6 or later
Fixed in 11.6.5.312.1.5.313.1.3.6
Interim mitigation

Upgrade BIG-IP to version 16.0.1.1, 15.1.2, 14.1.3.1, 13.1.3.6, 12.1.5.3, or 11.6.5.3 or later. If upgrading is not immediately possible, review virtual server configurations and consider disabling MPTCP at the global level if not required.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

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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-2021-23004 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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