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Big Ip Access Policy ManagerApplication · F5

CVE-2020-27719

MEDIUM · 6.1 CVSS v3.1 Published 2020-12-24
Fix available
A fix is available. Upgrade to 14.1.3.1 / 15.1.1 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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 16.0.0-16.0.0.1, 15.1.0-15.1.0.5, and 14.1.0-14.1.3, a cross-site scripting (XSS) vulnerability exists in an undisclosed page of 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 · moderate confidence

A cross-site scripting (XSS) vulnerability exists in an undisclosed page of the BIG-IP Configuration utility affecting versions 14.1.0-14.1.3, 15.1.0-15.1.0.5, and 16.0.0-16.0.0.1. The CVSS 6.1 score indicates the vulnerability is network-exploitable but requires user interaction (such as clicking a crafted link) to execute malicious scripts in the context of a user's session.

MitigationApply the relevant hotfix/patch provided by F5 Networks for this CVE. Until a patch is applied, consider restricting access to the Configuration utility to trusted networks only and monitor for suspicious activity.

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, < 14.1.3.1>= 15.0.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Advanced Firewall ManagerApplication
Affected:>= 14.1.0, < 14.1.3.1>= 15.0.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Advanced Web Application FirewallApplication
Affected:>= 14.1.0, < 14.1.3.1>= 15.0.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip AnalyticsApplication
Affected:>= 14.1.0, < 14.1.3.1>= 15.0.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Application Acceleration ManagerApplication
Affected:>= 14.1.0, < 14.1.3.1>= 15.0.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Application Security ManagerApplication
Affected:>= 14.1.0, < 14.1.3.1>= 15.0.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Ddos Hybrid DefenderApplication
Affected:>= 14.1.0, < 14.1.3.1>= 15.0.0, < 15.1.1>= 16.0.0, < 16.0.1
Big Ip Domain Name SystemApplication
Affected:>= 14.1.0, < 14.1.3.1>= 15.0.0, < 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
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/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. Verify BIG-IP version is within affected range
    Run 'tmsh show sys version' or check the Configuration utility login page footer for the version number. Compare against: 14.1.0-14.1.3.x, 15.1.0-15.1.0.5, 16.0.0-16.0.0.1 (or more precisely: >= 14.1.0 and < 14.1.3.1; >= 15.0.0 and < 15.1.1; >= 16.0.0 and < 16.0.1)
    Affected if Installed version matches any of the vulnerable version ranges listed in the CVE
  2. Confirm Configuration utility (GUI) is accessible
    Attempt to access the BIG-IP Configuration utility web interface at the management IP on port 443 or 8443. Check if the login page loads.
    Affected if The Configuration utility is reachable over the network (this is required for the XSS to be exploitable)
  3. Check if any affected Big-IP modules are provisioned
    Run 'tmsh list sys provision' to list provisioned modules. The vulnerability affects APM, AFM, AFW, Analytics, AAM, ASM, DDoS Hybrid Defender, and DNS modules.
    Affected if Any of the affected modules (APM, AFM, AFW, Analytics, AAM, ASM, DDoS Hybrid Defender, DNS) are provisioned on the device
  4. Verify network exposure of management interface
    Review iRule configurations, VLAN settings, and access profiles to determine if the Configuration utility is exposed to untrusted networks. Check if the management interface is accessible from outside trusted networks.
    Affected if The Configuration utility is exposed to untrusted or public networks (the XSS is network-exploitable)

You are affected if your BIG-IP version falls within the vulnerable ranges (14.1.0-14.1.3.x, 15.1.0-15.1.0.5, 16.0.0-16.0.0.1), the Configuration utility is accessible, and it is exposed to networks where attackers could trick users into clicking malicious links.

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 14.1.3.1 / 15.1.1 / 16.0.1 or later
Fixed in 14.1.3.115.1.116.0.1
Interim mitigation

Apply the relevant hotfix/patch provided by F5 Networks for this CVE. Until a patch is applied, consider restricting access to the Configuration utility to trusted networks only and monitor for suspicious activity.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,820
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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-2020-27719 in production — separate from our analysis above.

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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