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Big Ip Access Policy ManagerApplication · F5

CVE-2019-6684

HIGH · 7.5 CVSS v3.1 Published 2019-12-23
Fix available
A fix is available. Upgrade to 13.1.3.2 / 14.1.2.3 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 versions 15.0.0-15.0.1.1, 14.0.0-14.1.2.2, 13.1.0-13.1.3.1, 12.1.0-12.1.5, and 11.5.2-11.6.5.1, under certain conditions, a multi-bladed BIG-IP Virtual Clustered Multiprocessing (vCMP) may drop broadcast packets when they are rebroadcast to the vCMP guest secondary blades. An attacker can leverage the fragmented broadcast IP packets to perform any type of fragmentation-based attack.

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

In multi-bladed F5 BIG-IP vCMP environments, fragmented broadcast IP packets are incorrectly dropped when being rebroadcast to vCMP guest secondary blades. This allows attackers to send specially crafted fragmented broadcast packets to cause denial of service or potentially exploit fragment-based attack vectors.

MitigationUpgrade F5 BIG-IP to versions beyond 15.0.1.1, 14.1.2.2, 13.1.3.1, 12.1.5, or 11.6.5.1 as appropriate. If upgrading is not immediately feasible, consider disabling vCMP if not required and implement network segmentation to limit exposure to untrusted networks.

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:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.5>= 13.0.0, < 13.1.3.2>= 14.0.0, < 14.1.2.3>= 15.0.0, < 15.1.0
Big Ip Advanced Firewall ManagerApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.5>= 13.0.0, < 13.1.3.2>= 14.0.0, < 14.1.2.3>= 15.0.0, < 15.1.0
Big Ip AnalyticsApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.5>= 13.0.0, < 13.1.3.2>= 14.0.0, < 14.1.2.3>= 15.0.0, < 15.1.0
Big Ip Application Acceleration ManagerApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.5>= 13.0.0, < 13.1.3.2>= 14.0.0, < 14.1.2.3>= 15.0.0, < 15.1.0
Big Ip Application Security ManagerApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.5>= 13.0.0, < 13.1.3.2>= 14.0.0, < 14.1.2.3>= 15.0.0, < 15.1.0
Big Ip Domain Name SystemApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.5>= 13.0.0, < 13.1.3.2>= 14.0.0, < 14.1.2.3>= 15.0.0, < 15.1.0
Big Ip Fraud Protection ServiceApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.5>= 13.0.0, < 13.1.3.2>= 14.0.0, < 14.1.2.3>= 15.0.0, < 15.1.0
Big Ip Global Traffic ManagerApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.5>= 13.0.0, < 13.1.3.2>= 14.0.0, < 14.1.2.3>= 15.0.0, < 15.1.0

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 vCMP is enabled on the BIG-IP system
    Run 'tmsh show vcmp info' or check the vCMP status in the BIG-IP configuration via 'tmsh list sys vcmp'
    Affected if vCMP is enabled and running - if vCMP is disabled, the system is not affected by this vulnerability
  2. Confirm the BIG-IP version falls within affected ranges
    Run 'tmsh show sys version' or check via the web UI under Device > Overview > System Information. Compare the version to: 11.5.2-11.6.5, 12.1.0-12.1.5, 13.0.0-13.1.3.1, 14.0.0-14.1.2.2, or 15.0.0-15.1.0
    Affected if The installed version is within any of the listed affected ranges
  3. Confirm multi-bladed vCMP deployment
    Run 'tmsh show vcmp guest' to list all vCMP guests and their blade assignments. Check that secondary blades are hosting vCMP guests
    Affected if The system uses multiple blades with vCMP guests on secondary blades - the vulnerability affects rebroadcast to secondary blade guests specifically
  4. Verify broadcast traffic handling to vCMP guests
    Inspect network configuration for broadcast packet flow: check if there are any broadcast or multicast policies targeting vCMP guests. Review 'tmsh list net broadcast' and related network configuration
    Affected if Broadcast traffic is configured to be forwarded to vCMP guests in a multi-bladed environment

A system is affected if it runs a vulnerable BIG-IP version, has vCMP enabled, uses multiple blades with vCMP guests on secondary blades, and handles broadcast traffic to those guests.

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 / 14.1.2.3 / 15.1.0 or later
Fixed in 13.1.3.214.1.2.315.1.0
Interim mitigation

Upgrade F5 BIG-IP to versions beyond 15.0.1.1, 14.1.2.2, 13.1.3.1, 12.1.5, or 11.6.5.1 as appropriate. If upgrading is not immediately feasible, consider disabling vCMP if not required and implement network segmentation to limit exposure to untrusted networks.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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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-2019-6684 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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