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Big Ip Access Policy ManagerApplication · F5

CVE-2023-40534

HIGH · 7.5 CVSS v3.1 Published 2023-10-10
Fix available
A fix is available. Upgrade to 16.1.4.1 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
When a client-side HTTP/2 profile and the HTTP MRF Router option are enabled for a virtual server, and an iRule using the HTTP_REQUEST event or Local Traffic Policy are associated with the virtual server, undisclosed requests can cause 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 · moderate confidence

A denial of service vulnerability in F5 BIG-IP where the combination of client-side HTTP/2 profile, HTTP MRF Router option, and an iRule with HTTP_REQUEST event or Local Traffic Policy on a virtual server allows undisclosed requests to crash the TMM (Traffic Management Microkernel).

MitigationApply vendor-supplied patches for affected F5 BIG-IP versions. Alternatively, temporarily disable either the HTTP/2 profile, the MRF Router option, or the iRule/Local Traffic Policy until patching is 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 Access Policy ManagerApplication
Affected:>= 16.1.0, < 16.1.4.1= 17.1.0
Big Ip Advanced Firewall ManagerApplication
Affected:>= 16.1.0, < 16.1.4.1= 17.1.0
Big Ip Advanced Web Application FirewallApplication
Affected:>= 16.1.0, < 16.1.4.1= 17.1.0
Big Ip AnalyticsApplication
Affected:>= 16.1.0, < 16.1.4.1= 17.1.0
Big Ip Application Acceleration ManagerApplication
Affected:>= 16.1.0, < 16.1.4.1= 17.1.0
Big Ip Application Security ManagerApplication
Affected:>= 16.1.0, < 16.1.4.1= 17.1.0
Big Ip Application Visibility And ReportingApplication
Affected:>= 16.1.0, < 16.1.4.1= 17.1.0
Big Ip Carrier Grade NatApplication
Affected:>= 16.1.0, < 16.1.4.1= 17.1.0

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 the installed BIG-IP version
    Run 'tmsh show sys version' or 'bigpipe version' from the command line. Alternatively, check the BIG-IP GUI under System > Software Management > Image List or System > About.
    Affected if The version is 16.1.0 through 16.1.3.x (any 16.1.0 <= version < 16.1.4.1) or exactly 17.1.0.
  2. Identify HTTP/2 profiles in use
    Run 'tmsh list ltm profile http2' to list all HTTP/2 profiles configured on the system. Note the profile names and the virtual servers they are assigned to.
    Affected if Any HTTP/2 profile exists and is assigned to a virtual server.
  3. Check if HTTP MRF Router option is enabled
    Run 'tmsh list ltm profile http2 <profile_name>' for each HTTP/2 profile found and look for 'mrf-router enabled'. Alternatively, check via GUI under Local Traffic > Profiles > HTTP/2 > the specific profile.
    Affected if The mrf-router option is set to enabled on any HTTP/2 profile.
  4. Identify iRules with HTTP_REQUEST events
    Run 'tmsh list ltm rule' to list all iRules, then search for 'when HTTP_REQUEST' within the iRule content. Identify which virtual servers these iRules are assigned to.
    Affected if Any iRule containing an HTTP_REQUEST event is attached to a virtual server that also has an HTTP/2 profile.
  5. Check for Local Traffic Policies
    Run 'tmsh list ltm policy' to list all Local Traffic Policies. Identify which virtual servers have active policies attached.
    Affected if Any Local Traffic Policy is assigned to a virtual server that also has an HTTP/2 profile.

The environment is affected if the BIG-IP version is 16.1.0 through 16.1.3.x or 17.1.0, AND a virtual server has an HTTP/2 profile with MRF Router enabled AND either an iRule with HTTP_REQUEST event or a Local Traffic Policy attached.

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 16.1.4.1 or later
Fixed in 16.1.4.1
Interim mitigation

Apply vendor-supplied patches for affected F5 BIG-IP versions. Alternatively, temporarily disable either the HTTP/2 profile, the MRF Router option, or the iRule/Local Traffic Policy until patching is feasible.

Recommended fix High confidence

BIG-IP 16.1.4.1 or later (16.1.x); BIG-IP 17.1.1 or later (17.1.x)

  1. 1. Identify all BIG-IP modules running affected versions (16.1.0-16.1.4.0 or 17.1.0)
  2. 2. Identify virtual servers using client-side HTTP/2 profiles with HTTP MRF Router option enabled
  3. 3. Identify iRules using HTTP_REQUEST event or Local Traffic Policies associated with those virtual servers
  4. 4. Schedule a maintenance window for the upgrade
  5. 5. Back up the BIG-IP configuration
  6. 6. Upgrade to BIG-IP version 16.1.4.1 or later (for 16.1.x installations)
  7. 7. For 17.1.0 installations, upgrade to 17.1.1 or later
  8. 8. Verify the upgrade was successful and services are running
Caveat Review release notes for any compatibility notes between 16.1.x and 16.1.4.1, or between 17.1.0 and 17.1.1

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
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,280
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,648.

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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-2023-40534 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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