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Big Ip Access Policy ManagerApplication · F5

CVE-2020-5940

MEDIUM · 5.4 CVSS v3.1 Published 2020-11-05
Fix available
A fix is available. Upgrade to 14.1.2.4 / 15.1.1 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

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 versions 16.0.0-16.0.0.1, 15.1.0-15.1.0.5, and 14.1.0-14.1.2.3, a stored cross-site scripting (XSS) vulnerability exists in an undisclosed page of the BIG-IP Traffic Management User Interface (TMUI), also known as the BIG-IP Configuration utility.

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 stored cross-site scripting (XSS) vulnerability exists in the BIG-IP Traffic Management User Interface (TMUI) configuration utility. The vulnerability allows malicious JavaScript to be persistently stored on an undisclosed page and executed when other users view the compromised content.

MitigationUpgrade BIG-IP to versions 16.0.0.2+, 15.1.0.6+, or 14.1.2.4+ as specified in F5 advisory. Alternatively, restrict access to the TMUI to trusted networks only.

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:>= 14.1.0, < 14.1.2.4>= 15.1.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Advanced Firewall ManagerApplication
Affected:>= 14.1.0, < 14.1.2.4>= 15.1.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip AnalyticsApplication
Affected:>= 14.1.0, < 14.1.2.4>= 15.1.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Application Acceleration ManagerApplication
Affected:>= 14.1.0, < 14.1.2.4>= 15.1.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Application Security ManagerApplication
Affected:>= 14.1.0, < 14.1.2.4>= 15.1.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Domain Name SystemApplication
Affected:>= 14.1.0, < 14.1.2.4>= 15.1.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Edge GatewayWeb browser
Affected:>= 14.1.0, < 14.1.2.4>= 15.1.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Fraud Protection ServiceApplication
Affected:>= 14.1.0, < 14.1.2.4>= 15.1.0, < 15.1.1>= 16.0.0, < 16.0.1

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
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/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 BIG-IP version via TMUI
    Log into the Traffic Management User Interface (TMUI) and navigate to System > Software Management > ISO Image, or check the login page footer which displays the version number
    Affected if The displayed version falls within these ranges: 14.1.0 to 14.1.2.3, 15.1.0 to 15.1.0.x, or 16.0.0 to 16.0.0.x (any version before 14.1.2.4, 15.1.1, or 16.0.1)
  2. Check BIG-IP version via command line
    Execute 'tmsh show /sys version' or 'bigpipe version' from the command line to retrieve the installed version
    Affected if The version output matches the affected ranges: 14.1.x before 14.1.2.4, 15.1.x before 15.1.1, or 16.0.x before 16.0.1
  3. Determine if TMUI is network-accessible
    Attempt to access the TMUI web interface from an untrusted network or check the BIG-IP self IP access list configuration for port 443/tmsh
    Affected if The TMUI (typically on port 443) is reachable from untrusted networks rather than being restricted to management IPs or localhost only
  4. Identify installed BIG-IP modules
    Run 'tmsh list sys module' or check System > Resource information in TMUI to see which modules (APM, AFM, ASM, etc.) are provisioned
    Affected if Any of the affected modules (APM, AFM, Analytics, AAM, ASM, DNS, Edge Gateway, FPS) are installed on a version within the affected ranges

You are affected if your BIG-IP version is 14.1.0-14.1.2.3, 15.1.0-15.1.0.x, or 16.0.0-16.0.0.x and the TMUI is accessible from your network.

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 14.1.2.4 / 15.1.1 / 16.0.1 or later
Fixed in 14.1.2.415.1.116.0.1
Interim mitigation

Upgrade BIG-IP to versions 16.0.0.2+, 15.1.0.6+, or 14.1.2.4+ as specified in F5 advisory. Alternatively, restrict access to the TMUI to trusted networks only.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
25.0 hours of engineering $4,400
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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-2020-5940 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