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CVE-2020-0646

Microsoft .NET Framework Remote Code Execution Vulnerability

A remote code execution vulnerability exists when the Microsoft .NET Framework fails to validate input properly, aka '.NET Framework Remote Code Execution Injection Vulnerability'.

CheckOps priority index
9.3/10 Patch within 24 h
Severity9.8
Probability9.9
Exploitation4/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 99.2% higher than 99.9% of CVEs
CVSS 3.1 9.8 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:
Exploited for 1,826 days 03 Nov 2021
CISA due date 03 May 2022 for US federal agencies

Exploitation probability EPSS · FIRST

05010026 Sep05 Oct15 Oct24 Oct02 Nov
EPSS probability (%)Percentile among all CVEs

Exploitation signals 4 / 5

  • KEV catalog (CISA)03 Nov 2021
  • Exploited in EUVD (ENISA)03 Nov 2021
  • Used by ransomwareno
  • EPSS above 10 %99.2%
  • No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Affected products

Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for 32-bit SystemsMicrosoft .NET Framework 3.5 AND 4.7.2 on Windows Server 2019Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1803 for x64-based SystemsMicrosoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1803 for 32-bit SystemsMicrosoft .NET Framework 4.5.2Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1909 for 32-bit SystemsMicrosoft .NET Framework 3.5.1Microsoft .NET Framework 4.8 on Windows 10 Version 1803 for x64-based SystemsMicrosoft .NET Framework 3.5Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for 32-bit SystemsMicrosoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016 (Server Core installation)Microsoft .NET Framework 3.5 AND 4.7.1/4.7.2 on Windows 10 Version 1709 for 32-bit SystemsMicrosoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1909 for x64-based SystemsMicrosoft .NET Framework 3.5 AND 4.7.2 on Windows Server, version 1803 (Server Core Installation)Microsoft .NET Framework 4.8 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2Microsoft .NET Framework 4.8 on Windows 10 Version 1709 for x64-based SystemsMicrosoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1903 for 32-bit SystemsMicrosoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for x64-based SystemsMicrosoft .NET Framework 4.8 on Windows 10 Version 1607 for 32-bit SystemsMicrosoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for x64-based SystemsMicrosoft .NET Framework 3.5 AND 4.7.2 on Windows 10 for x64-based SystemsMicrosoft .NET Framework 4.6Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for x64-based SystemsMicrosoft .NET Framework 4.8 on Windows Server 2012 R2Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for x64-based SystemsMicrosoft .NET Framework 3.0Microsoft .NET Framework 3.5 AND 4.8 on Windows Server, version 1909 (Server Core installation)Microsoft .NET Framework 4.8 on Windows Server 2016Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2019Microsoft .NET Framework 4.8 on Windows RT 8.1Microsoft .NET Framework 4.8 on Windows Server 2012 (Server Core installation)Microsoft .NET Framework 3.5 AND 4.7.1/4.7.2 on Windows 10 Version 1709 for x64-based SystemsMicrosoft .NET Framework 4.8 on Windows Server 2008 R2 for x64-based Systems Service Pack 1Microsoft .NET Framework 4.8 on Windows 8.1 for x64-based systemsMicrosoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1903 for x64-based SystemsMicrosoft .NET Framework 4.8 on Windows 10 Version 1803 for 32-bit SystemsMicrosoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016Microsoft .NET Framework 4.8 on Windows 7 for 32-bit Systems Service Pack 1Microsoft .NET Framework 4.8 on Windows 7 for x64-based Systems Service Pack 1Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2019 (Server Core installation)Microsoft .NET Framework 4.8 on Windows Server 2016 (Server Core installation)Microsoft .NET Framework 4.8 on Windows 8.1 for 32-bit systemsMicrosoft .NET Framework 4.8 on Windows Server, version 1803 (Server Core Installation)Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 for 32-bit SystemsMicrosoft .NET Framework 4.8 on Windows Server 2012 R2 (Server Core installation)Microsoft .NET Framework 3.5 AND 4.7.2 on Windows Server 2019 (Server Core installation)Microsoft .NET Framework 4.8 on Windows Server 2012Microsoft .NET Framework 3.5 AND 4.8 on Windows Server, version 1903 (Server Core installation)Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for 32-bit SystemsMicrosoft .NET Framework 4.8 on Windows 10 Version 1709 for 32-bit Systems.NET Framework
Affected versions
  • Windows 7 for x64-based Systems Service Pack 1
  • unspecified
  • Windows RT 8.1
  • Windows Server 2012 (Server Core installation)
  • Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
  • Windows 7 for 32-bit Systems Service Pack 1
  • Windows Server 2008 R2 for x64-based Systems Service Pack 1
  • Windows 10 Version 1607 for 32-bit Systems
  • Windows 8.1 for x64-based systems
  • Windows Server 2012
  • Windows Server 2008 for 32-bit Systems Service Pack 2
  • Windows Server 2012 R2
Weaknesses (CWE)
CWE-91

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

  1. Published

  2. Exploitation reported (ENISA)

  3. Added to the KEV catalog

  4. CISA remediation due date

  5. EPSS peak: 99.2%

References

Other exploited vulnerabilities from the same vendor

  • CVE-2026-96951Microsoft Windows Command Injection Vulnerability
    5.6 · Actively exploited
  • CVE-2026-65660Microsoft SharePoint Code Injection Vulnerability
    5.0 · Actively exploited
  • CVE-2026-85880Microsoft Windows Heap-Based Buffer Overflow Vulnerability
    4.3 · Actively exploited
  • CVE-2026-81963Microsoft Windows Link Following Vulnerability
    4.3 · Actively exploited
  • CVE-2019-1068Microsoft SQL Server Remote Code Execution Vulnerability
    7.0 · Actively exploited
  • CVE-2026-69836Microsoft Entra
    5.3 · Actively exploited

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Sources: CISA KEV · ENISA EUVD · FIRST EPSS · OSV. Public data aggregated by CheckOps, updated automatically. Source texts remain the property of their authors. All exploited vulnerabilities