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Big Ip Access Policy ManagerApplication · F5

CVE-2019-6677

HIGH · 7.5 CVSS v3.1 Published 2019-12-23
Fix available
A fix is available. Upgrade to 13.1.3.2 / 14.0.1.1 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 BIG-IP versions 15.0.0-15.0.1, 14.1.0-14.1.2, 14.0.0-14.0.1, 13.1.0-13.1.3.1, and 12.1.0-12.1.5, under certain conditions when using custom TCP congestion control settings in a TCP profile, TMM stops processing traffic when processed by an iRule.

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 exists in F5 BIG-IP where TMM (Traffic Management Module) stops processing traffic when custom TCP congestion control settings in a TCP profile are combined with iRule processing. This affects specific versions from 12.1.0 through 15.0.1.

MitigationApply the appropriate F5 BIG-IP hotfix or upgrade to a patched version outside the affected version ranges. This is a service-affecting DoS vulnerability requiring prompt remediation.

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, <= 12.1.5>= 13.1.0, < 13.1.3.2>= 14.0.0, < 14.0.1.1>= 14.1.0, < 14.1.2.1>= 15.0.0, < 15.0.1.1
Big Ip Advanced Firewall ManagerApplication
Affected:>= 12.1.0, <= 12.1.5>= 13.1.0, < 13.1.3.2>= 14.0.0, < 14.0.1.1>= 14.1.0, < 14.1.2.1>= 15.0.0, < 15.0.1.1
Big Ip AnalyticsApplication
Affected:>= 12.1.0, <= 12.1.5>= 13.1.0, < 13.1.3.2>= 14.0.0, < 14.0.1.1>= 14.1.0, < 14.1.2.1>= 15.0.0, < 15.0.1.1
Big Ip Application Acceleration ManagerApplication
Affected:>= 12.1.0, <= 12.1.5>= 13.1.0, < 13.1.3.2>= 14.0.0, < 14.0.1.1>= 14.1.0, < 14.1.2.1>= 15.0.0, < 15.0.1.1
Big Ip Application Security ManagerApplication
Affected:>= 12.1.0, <= 12.1.5>= 13.1.0, < 13.1.3.2>= 14.0.0, < 14.0.1.1>= 14.1.0, < 14.1.2.1>= 15.0.0, < 15.0.1.1
Big Ip Domain Name SystemApplication
Affected:>= 12.1.0, <= 12.1.5>= 13.1.0, < 13.1.3.2>= 14.0.0, < 14.0.1.1>= 14.1.0, < 14.1.2.1>= 15.0.0, < 15.0.1.1
Big Ip Fraud Protection ServiceApplication
Affected:>= 12.1.0, <= 12.1.5>= 13.1.0, < 13.1.3.2>= 14.0.0, < 14.0.1.1>= 14.1.0, < 14.1.2.1>= 15.0.0, < 15.0.1.1
Big Ip Global Traffic ManagerApplication
Affected:>= 12.1.0, <= 12.1.5>= 13.1.0, < 13.1.3.2>= 14.0.0, < 14.0.1.1>= 14.1.0, < 14.1.2.1>= 15.0.0, < 15.0.1.1

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 BIG-IP software version
    Run 'tmsh show /sys version' or check System > Software Management > Software Images in the web UI
    Affected if The version falls within 12.1.0-12.1.5, 13.1.0-13.1.3.1, 14.0.0-14.0.1.0, 14.1.0-14.1.2.0, or 15.0.0-15.0.1.0
  2. List all TCP profiles on the system
    Run 'tmsh list /ltm profile tcp' to see all TCP profiles and their settings
    Affected if Any TCP profile has 'congestion-control' set to a non-default value (not 'default' or 'cubic' or 'bic')
  3. Identify iRules configured on the system
    Run 'tmsh list /ltm rule' to list all iRules, then run 'tmsh list /ltm virtual' to see which virtual servers reference iRules
    Affected if Any virtual server has one or more iRules assigned to it
  4. Check for the combination of custom TCP congestion control and iRules
    Cross-reference the TCP profiles with custom congestion control against virtual servers that have iRules assigned
    Affected if A virtual server uses a TCP profile with custom congestion control AND has iRules applied to it

You are affected if you are running an affected version AND have a virtual server using a TCP profile with custom congestion control settings combined with iRule processing.

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
Upgrade available Upgrade to 13.1.3.2 / 14.0.1.1 / 14.1.2.1 or later
Fixed in 13.1.3.214.0.1.114.1.2.1
Interim mitigation

Apply the appropriate F5 BIG-IP hotfix or upgrade to a patched version outside the affected version ranges. This is a service-affecting DoS vulnerability requiring prompt remediation.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.

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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-2019-6677 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