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Big Ip Local Traffic ManagerApplication · F5

CVE-2018-5533

HIGH · 7.5 CVSS v3.0 Published 2018-07-19
Fix available
A fix is available. Upgrade to after 12.1.2 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
Under certain conditions on F5 BIG-IP 13.0.0, 12.1.0-12.1.2, 11.6.0-11.6.3.1, or 11.5.0-11.5.6, TMM may core while processing SSL forward proxy traffic.

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 TMM (Traffic Management Microkernel) allows remote attackers to cause TMM to crash (core) when processing SSL forward proxy traffic under certain conditions. The vulnerability affects versions 13.0.0, 12.1.0-12.1.2, 11.6.0-11.6.3.1, and 11.5.0-11.5.6.

MitigationUpgrade F5 BIG-IP to a patched version (13.1.0+, 12.1.3+, 11.6.3.2+, or 11.5.7+) or apply the available hotfix per F5's advisory. If upgrading is not immediately feasible, consider disabling SSL forward proxy features if not required, or implement rate limiting on SSL proxy connections as a temporary mitigation.

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:>= 11.5.0, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Application Acceleration ManagerApplication
Affected:>= 11.5.0, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Advanced Firewall ManagerApplication
Affected:>= 11.5.0, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip AnalyticsApplication
Affected:>= 11.5.0, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Access Policy ManagerApplication
Affected:>= 11.5.0, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Application Security ManagerApplication
Affected:>= 11.5.0, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Domain Name SystemApplication
Affected:>= 11.5.0, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Edge GatewayWeb browser
Affected:>= 11.5.0, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 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
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. Identify BIG-IP version
    Run `tmsh show /sys version` or check the BIG-IP GUI under System > Software > Volume. Record the base version number.
    Affected if Version is 13.0.0, 12.1.0-12.1.2, 11.6.0-11.6.3.1, or 11.5.0-11.5.6.
  2. Verify SSL forward proxy is enabled
    Run `tmsh list /ltm profile client-ssl [profile-name]` for each SSL profile and check if `forward-proxy` is set to `enabled`. Alternatively, check via the GUI under Local Traffic > Profiles > SSL > Client.
    Affected if Any SSL client profile has forward proxy enabled.
  3. Confirm virtual servers use SSL forward proxy
    Run `tmsh list /ltm virtual` and cross-reference with SSL profiles that have forward proxy enabled. Look for virtual servers referencing the affected SSL profiles.
    Affected if Virtual servers are configured to use SSL profiles with forward proxy enabled.
  4. Check for recent TMM core dumps
    Inspect the directory `/var/core/` for recent core dump files, or run `tmsh show /ltm core` to list TMM core dumps.
    Affected if Recent TMM core dumps exist and coincide with SSL forward proxy traffic patterns.

The environment is affected if the installed BIG-IP version falls within the affected ranges AND SSL forward proxy is actively enabled on any virtual server.

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 12.1.2
Interim mitigation

Upgrade F5 BIG-IP to a patched version (13.1.0+, 12.1.3+, 11.6.3.2+, or 11.5.7+) or apply the available hotfix per F5's advisory. If upgrading is not immediately feasible, consider disabling SSL forward proxy features if not required, or implement rate limiting on SSL proxy connections as a temporary mitigation.

Fix this in Big Ip Local Traffic Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2018-5533 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