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Big Ip Local Traffic ManagerApplication · F5

CVE-2016-9253

HIGH · 7.5 CVSS v3.0 Published 2017-05-09
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
In F5 BIG-IP 12.1.0 through 12.1.2, specific websocket traffic patterns may cause a disruption of service for virtual servers configured to use the websocket profile.

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 in F5 BIG-IP versions 12.1.0 through 12.1.2 allows remote attackers to disrupt service for virtual servers using the websocket profile by sending specific websocket traffic patterns. The vulnerability has high availability impact with network-exploitable characteristics.

MitigationUpgrade BIG-IP to version 12.1.2 HF1 or later, or disable the websocket profile on affected virtual servers if upgrading is not immediately feasible.

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 Local Traffic ManagerApplication
Affected:= 12.1.0= 12.1.1= 12.1.2
Big Ip Application Acceleration ManagerApplication
Affected:= 12.1.0= 12.1.1= 12.1.2
Big Ip Advanced Firewall ManagerApplication
Affected:= 12.1.0= 12.1.1= 12.1.2
Big Ip AnalyticsApplication
Affected:= 12.1.0= 12.1.1= 12.1.2
Big Ip Access Policy ManagerApplication
Affected:= 12.1.0= 12.1.1= 12.1.2
Big Ip Application Security ManagerApplication
Affected:= 12.1.0= 12.1.1= 12.1.2
Big Ip Domain Name SystemApplication
Affected:= 12.1.0= 12.1.1= 12.1.2
Big Ip Link ControllerApplication
Affected:= 12.1.0= 12.1.1= 12.1.2

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. Determine BIG-IP version
    Run 'tmsh show sys version' or check the BIG-IP login page/version banner. The affected versions are exactly 12.1.0, 12.1.1, and 12.1.2.
    Affected if The installed version matches 12.1.0, 12.1.1, or 12.1.2.
  2. Identify virtual servers with websocket profile
    Run 'tmsh list ltm virtual one-line' and search for 'websocket' in the output, or use the Configuration Utility (GUI) to review virtual server profiles under Local Traffic > Virtual Servers.
    Affected if Any virtual server has the websocket profile enabled or assigned.
  3. Verify websocket profile status on each virtual server
    For each virtual server identified, run 'tmsh show ltm virtual <virtual_name>' and review the 'Profile' section, or inspect the virtual server configuration via 'tmsh list ltm virtual <virtual_name> profiles' to confirm websocket profile is active.
    Affected if The websocket profile shows as 'enabled' or 'available' in the virtual server configuration.

You are affected if your BIG-IP version is exactly 12.1.0, 12.1.1, or 12.1.2 AND at least one virtual server has the websocket profile enabled.

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 BIG-IP to version 12.1.2 HF1 or later, or disable the websocket profile on affected virtual servers if upgrading is not immediately feasible.

Fix this in Big Ip Local Traffic Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2016-9253 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