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Big Ip Local Traffic ManagerApplication · F5

CVE-2018-5500

MEDIUM · 5.9 CVSS v3.0 Published 2018-03-01
Fix available
A fix is available. Upgrade to after 12.1.3.1 or later.
See remediation →
68/100
Remediation priority · Elevated
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 F5 BIG-IP systems running 13.0.0, 12.1.0 - 12.1.3.1, or 11.6.1 - 11.6.2, every Multipath TCP (MCTCP) connection established leaks a small amount of memory. Virtual server using TCP profile with Multipath TCP (MCTCP) feature enabled will be affected by this issue.

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

F5 BIG-IP systems running 13.0.0, 12.1.0-12.1.3.1, or 11.6.1-11.6.2 contain a memory leak in the Multipath TCP (MCTCP) implementation. Every MCTCP connection established on a virtual server using a TCP profile with MCTCP enabled leaks a small amount of memory, which could lead to memory exhaustion over time with high connection volumes.

MitigationDisable the Multipath TCP (MCTCP) feature on affected virtual server TCP profiles, or upgrade to a patched BIG-IP version that addresses this memory leak vulnerability.

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:>= 11.6.1, <= 11.6.2>= 12.1.0, <= 12.1.3.1= 13.0.0
Big Ip Application Acceleration ManagerApplication
Affected:>= 11.6.1, <= 11.6.2>= 12.1.0, <= 12.1.3.1= 13.0.0
Big Ip Advanced Firewall ManagerApplication
Affected:>= 11.6.1, <= 11.6.2>= 12.1.0, <= 12.1.3.1= 13.0.0
Big Ip AnalyticsApplication
Affected:>= 11.6.1, <= 11.6.2>= 12.1.0, <= 12.1.3.1= 13.0.0
Big Ip Access Policy ManagerApplication
Affected:>= 11.6.1, <= 11.6.2>= 12.1.0, <= 12.1.3.1= 13.0.0
Big Ip Application Security ManagerApplication
Affected:>= 11.6.1, <= 11.6.2>= 12.1.0, <= 12.1.3.1= 13.0.0
Big Ip DnsApplication
Affected:>= 11.6.1, <= 11.6.2>= 12.1.0, <= 12.1.3.1= 13.0.0
Big Ip Link ControllerApplication
Affected:>= 11.6.1, <= 11.6.2>= 12.1.0, <= 12.1.3.1= 13.0.0

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:H/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 check the web UI under System > Software > Volume. Compare the installed version to the affected ranges: 13.0.0, 12.1.0-12.1.3.1, or 11.6.1-11.6.2.
    Affected if The installed version matches any of these three ranges.
  2. Identify TCP profiles with MCTCP enabled
    List all TCP profiles on the BIG-IP system using 'tmsh list ltm profile tcp' or via the web UI under Local Traffic > Profiles > Protocol > TCP. For each profile, check if 'multipath tcp' or 'mctcp' is set to 'enabled'.
    Affected if Any TCP profile has Multipath TCP (MCTCP) explicitly enabled.
  3. Identify virtual servers using MCTCP-enabled profiles
    List virtual servers and their associated TCP profiles using 'tmsh list ltm virtual' or via the web UI under Local Traffic > Virtual Servers. Cross-reference to determine if any virtual server uses a TCP profile with MCTCP enabled.
    Affected if Any virtual server is assigned a TCP profile with MCTCP enabled.
  4. Monitor memory consumption
    Review memory usage over time via 'tmsh show sys memory' or the web UI under Statistics > Module Statistics > Local Traffic. Look for steadily increasing memory usage on systems with high MCTCP connection volumes.
    Affected if Memory usage shows continuous growth correlating with MCTCP connection activity.

A system is affected if it runs a BIG-IP version in the 13.0.0, 12.1.0-12.1.3.1, or 11.6.1-11.6.2 range AND has at least one virtual server using a TCP profile with Multipath TCP (MCTCP) 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
Upgrade available Upgrade to a release after 12.1.3.1
Interim mitigation

Disable the Multipath TCP (MCTCP) feature on affected virtual server TCP profiles, or upgrade to a patched BIG-IP version that addresses this memory leak vulnerability.

Fix this in Big Ip Local Traffic Manager Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,440
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,304.

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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-2018-5500 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