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Big Ip Local Traffic ManagerApplication · F5

CVE-2019-6631

HIGH · 7.5 CVSS v3.1 Published 2019-07-03
Fix available
A fix is available. Upgrade to after 11.6.4 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 11.5.1-11.6.4, iRules performing HTTP header manipulation may cause an interruption to service when processing traffic handled by a Virtual Server with an associated HTTP profile, in specific circumstances, when the requests do not strictly conform to RFCs.

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 versions 11.5.1 through 11.6.4 where iRules that perform HTTP header manipulation can cause service interruption when processing traffic through Virtual Servers with HTTP profiles, specifically when receiving requests that do not strictly conform to RFC standards.

MitigationUpgrade BIG-IP to a patched version. Alternatively, review and modify iRules performing HTTP header manipulation to handle non-RFC-compliant requests, though upgrading is the recommended approach.

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:>= 11.5.2, <= 11.6.4
Big Ip Application Acceleration ManagerApplication
Affected:>= 11.5.2, <= 11.6.4
Big Ip Advanced Firewall ManagerApplication
Affected:>= 11.5.2, <= 11.6.4
Big Ip AnalyticsApplication
Affected:>= 11.5.2, <= 11.6.4
Big Ip Access Policy ManagerApplication
Affected:>= 11.5.2, <= 11.6.4
Big Ip Application Security ManagerApplication
Affected:>= 11.5.2, <= 11.6.4
Big Ip Domain Name SystemApplication
Affected:>= 11.5.2, <= 11.6.4
Big Ip Edge GatewayWeb browser
Affected:>= 11.5.2, <= 11.6.4

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 BIG-IP version is within affected range
    Run 'tmsh show sys version' or check the GUI under System > Software Management > ISO Image to identify the installed BIG-IP version.
    Affected if The installed version is between 11.5.2 and 11.6.4 inclusive.
  2. Identify Virtual Servers with HTTP profiles
    Run 'tmsh list ltm virtual one-line' and look for entries containing 'http' in the profile section, or review Virtual Server configurations in the GUI under Local Traffic > Virtual Servers.
    Affected if There are Virtual Servers configured with HTTP profiles enabled.
  3. Locate iRules performing HTTP header manipulation
    Run 'tmsh list ltm rule one-line' to list all iRules, then inspect each iRule for HTTP header commands such as 'HTTP::header', 'HTTP::header insert', 'HTTP::header remove', 'HTTP::header replace', or similar header manipulation commands.
    Affected if Any iRule contains commands that manipulate HTTP headers and is assigned to a Virtual Server with an HTTP profile.
  4. Confirm iRule assignment to affected Virtual Servers
    Run 'tmsh list ltm virtual <name> rules' for each Virtual Server with an HTTP profile to see which iRules are assigned, or review the Virtual Server GUI under Resources > iRules.
    Affected if An iRule performing HTTP header manipulation is assigned to a Virtual Server with an HTTP profile.

You are affected if your BIG-IP version is between 11.5.2 and 11.6.4 AND you have iRules that perform HTTP header manipulation assigned to Virtual Servers with HTTP profiles that could receive non-RFC-compliant requests.

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 a release after 11.6.4
Interim mitigation

Upgrade BIG-IP to a patched version. Alternatively, review and modify iRules performing HTTP header manipulation to handle non-RFC-compliant requests, though upgrading is the recommended approach.

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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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.

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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-2019-6631 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