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Actively exploited

CVE-2020-1464 Microsoft Windows Spoofing Vulnerability

Microsoft Windows contains a spoofing vulnerability when Windows incorrectly validates file signatures, allowing an attacker to bypass security features and load improperly signed files.

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

Our Assessment

Should You Worry?

Patch urgentlyCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 3 Nov 2021.
  • Rated High severity (CVSS 7.8, scored by Vendor).
  • 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

A spoofing vulnerability exists when Windows incorrectly validates file signatures. An attacker who successfully exploited this vulnerability could bypass security features and load improperly signed files. In an attack scenario, an attacker could bypass security features intended to prevent improperly signed files from being loaded. The update addresses the vulnerability by correcting how Windows validates file signatures.

Affected Versions

ProductVersions
Microsoft Windows 10 Version 180310.0.0 to before publication
Microsoft Windows 10 Version 180910.0.0 to before publication
Microsoft Windows Server 201910.0.0 to before publication
Microsoft Windows Server 2019 (Server Core installation)10.0.0 to before publication
Microsoft Windows 10 Version 190910.0.0 to before publication
Microsoft Windows Server, version 1909 (Server Core installation)10.0.0 to before publication

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 Microsoft Windows. 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 high, 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

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2020-1464
  3. CVE record: CVE-2020-1464
  4. FIRST EPSS
  5. medium.com/%40TalBeerySec/glueball-the-story-of-cve-2020-1464-50091a1f98bd
  6. krebsonsecurity.com/2020/08/microsoft-put-off-fixing-zero-day-for-2-years/
  7. portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1464
  8. blog.virustotal.com/2019/01/distribution-of-malicious-jar-appended.html