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Big Ip Access Policy ManagerApplication · F5

CVE-2020-5923

MEDIUM · 5.4 CVSS v3.1 Published 2020-08-26
Fix available
A fix is available. Upgrade to 11.6.5.2 / 12.1.5.2 or later.
See remediation →
59/100
Remediation priority · Elevated
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 BIG-IP versions 15.0.0-15.1.0.4, 14.1.0-14.1.2.6, 13.1.0-13.1.3.3, 12.1.0-12.1.5.1, and 11.6.1-11.6.5.1 and BIG-IQ versions 5.4.0-7.0.0, Self-IP port-lockdown bypass via IPv6 link-local addresses.

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

Self-IP port lockdown in F5 BIG-IP and BIG-IQ can be bypassed by using IPv6 link-local addresses, allowing attackers to reach services that should be blocked by the port lockdown feature.

MitigationUpgrade to a fixed version of BIG-IP/BIG-IQ. Until then, consider disabling IPv6 or implementing additional network-level filtering to block IPv6 link-local traffic if not required.

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:>= 11.6.1, < 11.6.5.2>= 12.1.0, < 12.1.5.2>= 13.1.0, < 13.1.3.4>= 14.1.0, < 14.1.2.7>= 15.0.0, < 15.1.0.5
Big Ip Advanced Firewall ManagerApplication
Affected:>= 11.6.1, < 11.6.5.2>= 12.1.0, < 12.1.5.2>= 13.1.0, < 13.1.3.4>= 14.1.0, < 14.1.2.7>= 15.0.0, < 15.1.0.5
Big Ip AnalyticsApplication
Affected:>= 11.6.1, < 11.6.5.2>= 12.1.0, < 12.1.5.2>= 13.1.0, < 13.1.3.4>= 14.1.0, < 14.1.2.7>= 15.0.0, < 15.1.0.5
Big Ip Application Acceleration ManagerApplication
Affected:>= 11.6.1, < 11.6.5.2>= 12.1.0, < 12.1.5.2>= 13.1.0, < 13.1.3.4>= 14.1.0, < 14.1.2.7>= 15.0.0, < 15.1.0.5
Big Ip Application Security ManagerApplication
Affected:>= 11.6.1, < 11.6.5.2>= 12.1.0, < 12.1.5.2>= 13.1.0, < 13.1.3.4>= 14.1.0, < 14.1.2.7>= 15.0.0, < 15.1.0.5
Big Ip Domain Name SystemApplication
Affected:>= 11.6.1, < 11.6.5.2>= 12.1.0, < 12.1.5.2>= 13.1.0, < 13.1.3.4>= 14.1.0, < 14.1.2.7>= 15.0.0, < 15.1.0.5
Big Ip Fraud Protection ServiceApplication
Affected:>= 11.6.1, < 11.6.5.2>= 12.1.0, < 12.1.5.2>= 13.1.0, < 13.1.3.4>= 14.1.0, < 14.1.2.7>= 15.0.0, < 15.1.0.5
Big Ip Global Traffic ManagerApplication
Affected:>= 11.6.1, < 11.6.5.2>= 12.1.0, < 12.1.5.2>= 13.1.0, < 13.1.3.4>= 14.1.0, < 14.1.2.7>= 15.0.0, < 15.1.0.5

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

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 the installed BIG-IP or BIG-IQ version
    Run 'tmsh show sys version' or 'tmsh list sys version' from the command line
    Affected if The version falls within any of these ranges: 11.6.1 to 11.6.5.2, 12.1.0 to 12.1.5.2, 13.1.0 to 13.1.3.4, 14.1.0 to 14.1.2.7, or 15.0.0 to 15.1.0.5
  2. Verify Self-IP port lockdown configuration exists
    Run 'tmsh list /net self-allow' to list port lockdown settings on Self-IPs
    Affected if Any Self-IP has port lockdown entries (tcp or udp ports defined) that are intended to restrict access
  3. Confirm IPv6 is enabled on the system
    Run 'tmsh list /net ipv6' or check if IPv6 addresses are assigned to Self-IPs via 'tmsh list /net self'
    Affected if IPv6 is enabled and IPv6 addresses are configured on Self-IPs, allowing attackers to use IPv6 link-local addresses to bypass port lockdown
  4. Test for IPv6 link-local reachability to protected services
    From an external system, attempt to connect to a service via the Self-IP's IPv6 link-local address (fe80::/10 prefix) on a port that should be blocked by port lockdown
    Affected if Connections succeed on ports that are explicitly blocked in the port lockdown settings when using IPv6 link-local addresses

The system is affected if it runs a vulnerable BIG-IP/BIG-IQ version with port lockdown configured AND has IPv6 enabled, allowing IPv6 link-local traffic to bypass port restrictions.

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 11.6.5.2 / 12.1.5.2 / 13.1.3.4 or later
Fixed in 11.6.5.212.1.5.213.1.3.4
Interim mitigation

Upgrade to a fixed version of BIG-IP/BIG-IQ. Until then, consider disabling IPv6 or implementing additional network-level filtering to block IPv6 link-local traffic if not required.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,800
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,080.

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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-2020-5923 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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