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Big Ip Access Policy ManagerApplication · F5

CVE-2021-23039

HIGH · 7.5 CVSS v3.1 Published 2021-09-14
Fix available
A fix is available. Upgrade to 14.1.2.8 / 15.1.3 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 version 16.0.x before 16.0.1.2, 15.1.x before 15.1.3, 14.1.x before 14.1.2.8, and all versions of 13.1.x and 12.1.x, when IPSec is configured on a BIG-IP system, undisclosed requests from an authorized remote (IPSec) peer, which already has a negotiated Security Association, can cause the Traffic Management Microkernel (TMM) 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

Denial of service vulnerability in F5 BIG-IP where an authorized IPSec peer with an already-negotiated Security Association can send undisclosed requests that cause the Traffic Management Microkernel (TMM) to terminate, disrupting all traffic processing.

MitigationUpgrade BIG-IP to fixed versions (16.0.1.2+, 15.1.3+, 14.1.2.8+) or disable IPSec if not required, as the vulnerability is triggered by requests from an already-authenticated IPSec peer.

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:>= 12.1.0, <= 12.1.6>= 13.1.0, <= 13.1.4>= 14.1.0, < 14.1.2.8>= 15.1.0, < 15.1.3>= 16.0.0, < 16.0.1.2
Big Ip Advanced Firewall ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, <= 13.1.4>= 14.1.0, < 14.1.2.8>= 15.1.0, < 15.1.3>= 16.0.0, < 16.0.1.2
Big Ip AnalyticsApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, <= 13.1.4>= 14.1.0, < 14.1.2.8>= 15.1.0, < 15.1.3>= 16.0.0, < 16.0.1.2
Big Ip Application Acceleration ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, <= 13.1.4>= 14.1.0, < 14.1.2.8>= 15.1.0, < 15.1.3>= 16.0.0, < 16.0.1.2
Big Ip Application Security ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, <= 13.1.4>= 14.1.0, < 14.1.2.8>= 15.1.0, < 15.1.3>= 16.0.0, < 16.0.1.2
Big Ip Domain Name SystemApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, <= 13.1.4>= 14.1.0, < 14.1.2.8>= 15.1.0, < 15.1.3>= 16.0.0, < 16.0.1.2
Big Ip Fraud Protection ServiceApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, <= 13.1.4>= 14.1.0, < 14.1.2.8>= 15.1.0, < 15.1.3>= 16.0.0, < 16.0.1.2
Big Ip Global Traffic ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, <= 13.1.4>= 14.1.0, < 14.1.2.8>= 15.1.0, < 15.1.3>= 16.0.0, < 16.0.1.2

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. Check BIG-IP version
    Run command 'tmsh show sys version' or check System > Information > Version in the web UI to obtain the installed version number
    Affected if The version falls within any of these affected ranges: 12.1.0-12.1.6, 13.1.0-13.1.4, 14.1.0-14.1.2.7, 15.1.0-15.1.2, or 16.0.0-16.0.1.1
  2. Verify IPSec is configured
    Run 'tmsh list net ipsec' to list all IPSec tunnel or policy configurations, or check under Network > IPSec in the web UI
    Affected if Any IPSec tunnels or policies are configured on the device (the vulnerability requires an already-negotiated Security Association to trigger the flaw)
  3. Confirm IPSec peers are active
    Run 'tmsh show net ipsec' or 'tmsh show net ipsec ike' to see active IPSec Security Associations and peer status
    Affected if There are active IPSec SAs with peers, meaning traffic can be processed through the IPSec tunnel (an active SA is required for the attack to be possible)

You are affected if your BIG-IP runs an affected version AND has IPSec tunnels configured with active peer connections, as the vulnerability is triggered by requests from an already-authenticated IPSec peer.

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 14.1.2.8 / 15.1.3 / 16.0.1.2 or later
Fixed in 14.1.2.815.1.316.0.1.2
Interim mitigation

Upgrade BIG-IP to fixed versions (16.0.1.2+, 15.1.3+, 14.1.2.8+) or disable IPSec if not required, as the vulnerability is triggered by requests from an already-authenticated IPSec peer.

Recommended fix High confidence

14.1.2.8+ or 15.1.3+ or 16.0.1.2+ (depending on current branch)

  1. Identify the currently installed BIG-IP version using 'tmsh show sys version' or the web UI.
  2. If running 12.1.x or 13.1.x, note these versions have reached End of Technical Support (EoTS) and require upgrade to a currently supported version.
  3. If running 14.1.x (14.1.0 to 14.1.2.7), upgrade to 14.1.2.8 or later.
  4. If running 15.1.x (15.1.0 to 15.1.2.x), upgrade to 15.1.3 or later.
  5. If running 16.0.x (16.0.0 to 16.0.1.1), upgrade to 16.0.1.2 or later.
  6. Download the appropriate hotfix from support.f5.com and follow F5's upgrade documentation.
  7. After upgrade, verify the version with 'tmsh show sys version' and test IPSec functionality.
Caveat Upgrading BIG-IP software may cause temporary service disruption; review F5 release notes for behavior changes and ensure compatibility with existing configurations 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-2021-23039 in production — separate from our analysis above.

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