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Big Ip Advanced Web Application FirewallApplication · F5

CVE-2026-41227

HIGH · 7.5 CVSS v3.1 Published 2026-05-13
Fix available
A fix is available. Upgrade to after 17.5.1 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 an HTTP/2 virtual server with Layer 7 DoS Protection configured, undisclosed traffic can result in an increase in memory consumption causing the Traffic Management Microkernel (TMM) process 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

This is a denial-of-service vulnerability in F5 BIG-IP where specific undisclosed traffic sent to an HTTP/2 virtual server with Layer 7 DoS Protection enabled causes excessive memory consumption, leading to the Traffic Management Microkernel (TMM) process to crash and terminate.

MitigationApply the vendor-supplied patch or upgrade to a fixed version once available. Until then, consider disabling Layer 7 DoS Protection on affected virtual servers or implementing additional upstream filtering.

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:>= 17.1.0, <= 17.1.3>= 17.5.0, <= 17.5.1>= 16.1.0, <= 16.1.6
Big Ip Application Security ManagerApplication
Affected:>= 17.1.0, <= 17.1.3>= 17.5.0, <= 17.5.1>= 16.1.0, <= 16.1.6
Big Ip Ddos Hybrid DefenderApplication
Affected:>= 17.1.0, <= 17.1.3>= 17.5.0, <= 17.5.1>= 16.1.0, <= 16.1.6

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 product module
    Run the appropriate command to list installed F5 modules (such as tmsh show module or the system GUI module summary). Confirm the system is running one of: Advanced Web Application Firewall, Application Security Manager, or DDoS Hybrid Defender.
    Affected if The system is running any of these three modules.
  2. Check the BIG-IP software version
    Run the command to display the installed BIG-IP version (such as tmsh show version or tmsh show sys version). Compare the version number against the affected ranges: 17.1.0 through 17.1.3, 17.5.0 through 17.5.1, or 16.1.0 through 16.1.6.
    Affected if The installed version falls within any of these ranges.
  3. Identify HTTP/2 enabled virtual servers
    List the virtual servers configured on the BIG-IP system (such as tmsh list ltm virtual or via the Configuration utility). Identify which virtual servers have HTTP/2 protocol enabled.
    Affected if Any virtual server is configured to accept HTTP/2 traffic.
  4. Verify Layer 7 DoS Protection is enabled
    Examine the virtual servers identified in the previous step. Check whether Layer 7 DoS Protection (also known as DoS Protection Profile or Application DoS) is attached or enabled on those HTTP/2 virtual servers.
    Affected if Layer 7 DoS Protection is enabled on any HTTP/2 virtual server.

The system is affected if it runs one of the three modules, falls within the specified version ranges, has an HTTP/2 virtual server, AND has Layer 7 DoS Protection enabled on that 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 17.5.1
Interim mitigation

Apply the vendor-supplied patch or upgrade to a fixed version once available. Until then, consider disabling Layer 7 DoS Protection on affected virtual servers or implementing additional upstream filtering.

Recommended fix Moderate confidence

Upgrade to BIG-IP 17.5.2 or later (or the latest 17.x stable release)

  1. 1. Log in to the F5 management console (TMUI) or use BIG-IP TMSH.
  2. 2. Identify all virtual servers using HTTP/2 with Layer 7 DoS Protection enabled.
  3. 3. Verify current BIG-IP version by running: tmsh show /sys version
  4. 4. If version is within affected ranges (16.1.0-16.1.6, 17.1.0-17.1.3, or 17.5.0-17.5.1), plan for upgrade.
  5. 5. Back up current configuration using: tmsh save /sys config all-partitions
  6. 6. Download the appropriate hotfix or upgrade ISO from F5 Networks support portal (my.f5.com).
  7. 7. Upload and install the hotfix/upgrade following F5 deployment documentation.
  8. 8. After upgrade, verify the TMM process stability and monitor memory consumption.
Caveat Review F5 release notes for any breaking changes between current and target version; test in non-production environment first

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
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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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-2026-41227 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
  • 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