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Actively exploitedKnown ransomware use

CVE-2020-5902 F5 BIG-IP Traffic Management User Interface (TMUI) Remote Code Execution Vulnerability

F5 BIG-IP Traffic Management User Interface (TMUI) contains a remote code execution vulnerability in undisclosed pages.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 3 Nov 2021.
  • CISA lists it as known to be used in ransomware campaigns.
  • Rated Critical severity (CVSS 9.8, scored by CISA).
  • This product type is often exposed to the internet, which is where attackers scan for it first.
  • It has been in the catalogue for 1,829 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

In BIG-IP versions 15.0.0-15.1.0.3, 14.1.0-14.1.2.5, 13.1.0-13.1.3.3, 12.1.0-12.1.5.1, and 11.6.1-11.6.5.1, the Traffic Management User Interface (TMUI), also referred to as the Configuration utility, has a Remote Code Execution (RCE) vulnerability in undisclosed pages.

Affected Versions

ProductVersions
BIG-IP15.0.0-15.1.0.3, 14.1.0-14.1.2.5, 13.1.0-13.1.3.3, 12.1.0-12.1.5.1, 11.6.1-11.6.5.1

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for F5 BIG-IP. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply updates per vendor instructions.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated critical, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 3 May 2022 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

More Exploited F5 Flaws

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CVE-2026-94127F5 BIG-IP APM Heap-based Buffer Overflow VulnerabilityAdded 22 Sep 2026CVE-2025-53521F5 BIG-IP Stack-Based Buffer Overflow VulnerabilityAdded 27 Mar 2026CVE-2023-46748F5 BIG-IP Configuration Utility SQL Injection VulnerabilityAdded 31 Oct 2023CVE-2023-46747 · RansomwareF5 BIG-IP Configuration Utility Authentication Bypass VulnerabilityAdded 31 Oct 2023CVE-2022-1388 · RansomwareF5 BIG-IP Missing Authentication VulnerabilityAdded 10 May 2022CVE-2021-22991F5 BIG-IP Traffic Management Microkernel Buffer OverflowAdded 18 Jan 2022

All 8 exploited F5 vulnerabilities

Not Sure If You Are Exposed?

Our attack surface and vulnerability teams can check your internet-facing estate for CVE-2020-5902 and every other exploited flaw on the list.

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2020-5902
  3. CVE record: CVE-2020-5902
  4. FIRST EPSS
  5. support.f5.com/csp/article/K52145254
  6. packetstormsecurity.com/files/158333/BIG-IP-TMUI-Remote-Code-Execution.html
  7. packetstormsecurity.com/files/158334/BIG-IP-TMUI-Remote-Code-Execution.html
  8. packetstormsecurity.com/files/158366/F5-BIG-IP-TMUI-Directory-Traversal-File-Upload-Code-Execution.h
  9. kb.cert.org/vuls/id/290915
  10. criticalstart.com/f5-big-ip-remote-code-execution-exploit/
  11. badpackets.net/over-3000-f5-big-ip-endpoints-vulnerable-to-cve-2020-5902/
  12. packetstormsecurity.com/files/158414/Checker-CVE-2020-5902.html