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Big Ip Access Policy ManagerApplication · F5

CVE-2015-8240

HIGH · 7.5 CVSS v3.0 Published 2016-04-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
The Traffic Management Microkernel (TMM) in F5 BIG-IP LTM, AAM, AFM, Analytics, APM, ASM, GTM, Link Controller, and BIG-IP PEM before 11.4.1 HF10, 11.5.x before 11.5.4, and 11.6.x before 11.6.0 HF6 and BIG-IP PSM before 11.4.1 HF10 does not properly handle TCP options, which allows remote attackers to cause a denial of service via unspecified vectors, related to the tm.minpathmtu database variable.

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

The F5 BIG-IP TMM (Traffic Management Microkernel) fails to properly handle certain TCP options, causing a denial of service condition when malformed or crafted TCP options are processed. The vulnerability is tied to the tm.minpathmtu database variable, which controls path MTU handling. Remote attackers can trigger the issue without authentication.

MitigationUpgrade F5 BIG-IP to version 11.4.1 HF10, 11.5.4, or 11.6.0 HF6 or later to patch this vulnerability. Organizations unable to upgrade immediately should consider network-level filtering of suspicious TCP options as a temporary measure.

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:= 11.4.1= 11.5.3= 11.6.0
Big Ip Advanced Firewall ManagerApplication
Affected:= 11.4.1= 11.5.3= 11.6.0
Big Ip AnalyticsApplication
Affected:= 11.4.1= 11.5.3= 11.6.0
Big Ip Application Acceleration ManagerApplication
Affected:= 11.4.1= 11.5.3= 11.6.0
Big Ip Application Security ManagerApplication
Affected:= 11.4.1= 11.5.3= 11.6.0
Big Ip Global Traffic ManagerApplication
Affected:= 11.4.1= 11.5.3= 11.6.0
Big Ip Link ControllerApplication
Affected:= 11.4.1= 11.5.3= 11.6.0
Big Ip Local Traffic ManagerApplication
Affected:= 11.4.1= 11.5.3= 11.6.0

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:3.0/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 'tmsh show /sys version' or 'b version' to retrieve the installed BIG-IP version
    Affected if Version is exactly 11.4.1, 11.5.3, or 11.6.0
  2. Verify TMM is active
    Run 'tmsh show /tmm status' to confirm the Traffic Management Microkernel is running
    Affected if TMM is active and processing traffic
  3. Inspect tm.minpathmtu database variable
    Run 'b db tm.minpathmtu' or 'tmsh list /sys db tm.minpathmtu' to check the current value of this variable
    Affected if tm.minpathmtu is configured (value exists) and TMM is processing traffic with that setting enabled
  4. Confirm TCP processing is enabled
    Run 'tmsh show /net tcp' to verify TCP profile handling is active
    Affected if TCP profiles are in use and TMM is handling TCP connections

A system is affected if it runs BIG-IP version 11.4.1, 11.5.3, or 11.6.0 with TMM active and the tm.minpathmtu variable configured, allowing remote attackers to trigger denial of service via malformed TCP options without authentication.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade F5 BIG-IP to version 11.4.1 HF10, 11.5.4, or 11.6.0 HF6 or later to patch this vulnerability. Organizations unable to upgrade immediately should consider network-level filtering of suspicious TCP options as a temporary measure.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2015-8240 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