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Big Ip Access Policy ManagerApplication · F5

CVE-2020-5876

HIGH · 8.1 CVSS v3.1 Published 2020-04-30
Fix available
A fix is available. Upgrade to after 15.1.0.3 or later.
See remediation →
90/100
Remediation priority · Urgent
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 15.0.0-15.0.1.3, 14.1.0-14.1.2.3, 13.1.0-13.1.3.3, 12.1.0-12.1.5.1, and 11.6.1-11.6.5.1, a race condition exists where mcpd and other processes may make unencrypted connection attempts to a new configuration sync peer. The race condition can occur when changing the ConfigSync IP address of a peer, adding a new peer, or when the Traffic Management Microkernel (TMM) first starts up.

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

A race condition in F5 BIG-IP allows mcpd and other processes to attempt unencrypted connections to configuration sync peers during peer IP changes, new peer additions, or TMM startup. This exposes configuration data in transit.

MitigationUpgrade BIG-IP to a version beyond the affected ranges (15.1.2.4+, 14.1.2.4+, 13.1.3.4+, 12.1.5.2+, 11.6.5.2+) or apply the available hotfix. Ensure ConfigSync is configured to use encrypted communication.

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, <= 11.6.5.1>= 12.1.0, <= 12.1.5.1>= 13.1.0, <= 13.1.3.3>= 14.1.0, <= 14.1.2.3>= 15.0.0, <= 15.1.0.3
Big Ip Advanced Firewall ManagerApplication
Affected:>= 11.6.1, <= 11.6.5.1>= 12.1.0, <= 12.1.5.1>= 13.1.0, <= 13.1.3.3>= 14.1.0, <= 14.1.2.3>= 15.0.0, <= 15.1.0.3
Big Ip AnalyticsApplication
Affected:>= 11.6.1, <= 11.6.5.1>= 12.1.0, <= 12.1.5.1>= 13.1.0, <= 13.1.3.3>= 14.1.0, <= 14.1.2.3>= 15.0.0, <= 15.1.0.3
Big Ip Application Acceleration ManagerApplication
Affected:>= 11.6.1, <= 11.6.5.1>= 12.1.0, <= 12.1.5.1>= 13.1.0, <= 13.1.3.3>= 14.1.0, <= 14.1.2.3>= 15.0.0, <= 15.1.0.3
Big Ip Application Security ManagerApplication
Affected:>= 11.6.1, <= 11.6.5.1>= 12.1.0, <= 12.1.5.1>= 13.1.0, <= 13.1.3.3>= 14.1.0, <= 14.1.2.3>= 15.0.0, <= 15.1.0.3
Big Ip Domain Name SystemApplication
Affected:>= 11.6.1, <= 11.6.5.1>= 12.1.0, <= 12.1.5.1>= 13.1.0, <= 13.1.3.3>= 14.1.0, <= 14.1.2.3>= 15.0.0, <= 15.1.0.3
Big Ip Fraud Protection ServiceApplication
Affected:>= 11.6.1, <= 11.6.5.1>= 12.1.0, <= 12.1.5.1>= 13.1.0, <= 13.1.3.3>= 14.1.0, <= 14.1.2.3>= 15.0.0, <= 15.1.0.3
Big Ip Global Traffic ManagerApplication
Affected:>= 11.6.1, <= 11.6.5.1>= 12.1.0, <= 12.1.5.1>= 13.1.0, <= 13.1.3.3>= 14.1.0, <= 14.1.2.3>= 15.0.0, <= 15.1.0.3

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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 product version
    Run the command 'tmsh show sys version' or check the BIG-IP UI under System > About. Note the exact version number (for example, 14.1.2.3).
    Affected if The installed version falls within any of these ranges: 11.6.1 to 11.6.5.1, 12.1.0 to 12.1.5.1, 13.1.0 to 13.1.3.3, 14.1.0 to 14.1.2.3, or 15.0.0 to 15.1.0.3.
  2. Confirm Device Service Clustering is enabled
    Run 'tmsh show /cm device' to list devices in the cluster. Then run 'tmsh show /cm device-group' to see if a sync device-group exists with more than one member.
    Affected if A device-group with multiple members exists, meaning ConfigSync is actively used between peers.
  3. Verify ConfigSync communication settings
    Run 'tmsh list /cm device-group <group-name>' and look for the 'type' and 'attributes' settings. Specifically check if 'device-sync' is set and whether encryption is configured.
    Affected if Device Service Clustering is enabled with sync groups but the ConfigSync traffic is not explicitly configured to use encrypted communication (the vulnerability allows unencrypted attempts during the race condition window).
  4. Check for recent sync peer changes
    Review logs in /var/log/mcpd for entries indicating device IP changes, new peer additions, or TMM restarts. Look for messages related to 'device' or 'config-sync' operations.
    Affected if Recent events involving peer IP changes, new peer additions, or TMM startup have occurred on the device, triggering the race condition window.

You are affected if your BIG-IP version is within the listed vulnerable ranges AND Device Service Clustering with multiple sync peers is enabled, particularly if ConfigSync encryption may not be consistently enforced during peer changes or TMM startup events.

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 15.1.0.3
Interim mitigation

Upgrade BIG-IP to a version beyond the affected ranges (15.1.2.4+, 14.1.2.4+, 13.1.3.4+, 12.1.5.2+, 11.6.5.2+) or apply the available hotfix. Ensure ConfigSync is configured to use encrypted communication.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation8.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,380
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,608.

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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-2020-5876 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data