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Big Ip Advanced Firewall ManagerApplication · F5

CVE-2024-21771

HIGH · 7.5 CVSS v3.1 Published 2024-02-14
Fix available
A fix is available. Upgrade to 15.1.9 / 16.1.4 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
For unspecified traffic patterns, BIG-IP AFM IPS engine may spend an excessive amount of time matching the traffic against signatures, resulting in Traffic Management Microkernel (TMM) restarting and traffic disruption.  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

BIG-IP AFM IPS engine can enter a resource exhaustion condition when processing certain unspecified traffic patterns, causing excessive CPU consumption during signature matching that leads to TMM (Traffic Management Microkernel) restart and traffic disruption.

MitigationApply the vendor-supplied patch for BIG-IP AFM when available; until then, consider disabling IPS functionality or implementing rate limiting on affected AFM units to mitigate potential DoS conditions.

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 Firewall ManagerApplication
Affected:>= 15.1.0, < 15.1.9>= 16.1.0, < 16.1.4= 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. Verify BIG-IP AFM module is provisioned
    Run 'tmsh list /sys provision' and look for 'afm' in the output, or check via web UI under System > Resource Provisioning > Advanced Firewall Manager (AFM).
    Affected if AFM module shows as provisioned (not 'none' or unlisted)
  2. Check installed BIG-IP version
    Run 'tmsh show /sys version' or 'tmsh list /sys version' to get the exact version number. Compare it against the affected ranges: 15.1.0-15.1.8, 16.1.0-16.1.3, or 17.1.0.
    Affected if Version falls within >= 15.1.0 < 15.1.9, >= 16.1.0 < 16.1.4, or equals 17.1.0
  3. Confirm IPS functionality is enabled in AFM policy
    Run 'tmsh list /security firewall policy' and inspect policies for 'ips-enforcement' or 'ips' settings set to 'enabled'. Alternatively, check via web UI under Security > Firewall > Policies and examine active AFM policies.
    Affected if Any AFM security policy has IPS enforcement explicitly enabled or uses an IPS profile
  4. Check for TMM restart events or high CPU during IPS processing
    Run 'tmsh show /sys tmm-stat' and review logs via 'tmsh show /log traffic' or '/var/log/ltm' for TMM restart messages (look for 'tmm terminated' or 'tmm restarted'). Look for timestamps correlating with traffic containing IPS signatures.
    Affected if Recent TMM restarts appear in logs or tmm-stat shows abnormal restarts, especially under high IPS traffic
  5. Identify active IPS profiles in use
    Run 'tmsh list /security ips profile' to list all IPS profiles. Run 'tmsh show /ltm virtual' to see which virtual servers reference these profiles via their security policies.
    Affected if Any virtual server references an AFM policy that applies IPS enforcement to incoming traffic

The environment is affected if AFM is provisioned, the BIG-IP version is in the vulnerable ranges, and IPS enforcement is actively enabled in any AFM security policy applied to traffic.

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 15.1.9 / 16.1.4 or later
Fixed in 15.1.916.1.4
Interim mitigation

Apply the vendor-supplied patch for BIG-IP AFM when available; until then, consider disabling IPS functionality or implementing rate limiting on affected AFM units to mitigate potential DoS conditions.

Recommended fix High confidence

15.1.9 (or later 15.1.x), 16.1.4 (or later 16.1.x), or 17.1.1 (or later 17.x)

  1. 1. Identify the current BIG-IP AFM version by running 'tmsh show sys version' or checking the web management console.
  2. 2. For version 15.1.x: Schedule maintenance window and upgrade to version 15.1.9 or later.
  3. 3. For version 16.1.x: Schedule maintenance window and upgrade to version 16.1.4 or later.
  4. 4. For version 17.1.0: Schedule maintenance window and upgrade to version 17.1.1 or later (the next available patch release).
  5. 5. After upgrade, verify TMM stability by monitoring system logs and running 'tmsh show sys tmm-info' to confirm normal operation.
  6. 6. Monitor for any recurring TMM restarts or IPS-related errors in /var/log/ltm.
Caveat Standard upgrade considerations apply - review F5 release notes for any configuration changes between versions, test in non-production environment first

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

Fix this in Big Ip Advanced Firewall Manager Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.

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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-2024-21771 in production — separate from our analysis above.

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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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data