Background exploitation KEV catalog Ransomware No authentication
CVE-2020-0796

Microsoft SMBv3 Remote Code Execution Vulnerability

A remote code execution vulnerability exists in the way that the Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain requests, aka 'Windows SMBv3 Client/Server Remote Code Execution Vulnerability'.

CheckOps priority index
10.0/10 Patch within 24 h
Severity10.0
Probability10.0
Exploitation5/5

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

EPSS · today 99.8% higher than 99.96% of CVEs
CVSS 3.1 10.0 AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:
Exploited for 1,727 days 10 Feb 2022
CISA due date 10 Aug 2022 for US federal agencies

Exploitation probability EPSS · FIRST

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

Exploitation signals 5 / 5

  • KEV catalog (CISA)10 Feb 2022
  • Exploited in EUVD (ENISA)10 Feb 2022
  • Used by ransomwareyes
  • EPSS above 10 %99.8%
  • 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

Windows Server, version 1903 (Server Core installation)Windows 10 Version 1903 for x64-based SystemsWindows 10 Version 1909 for x64-based SystemsWindows 10 Version 1909 for ARM64-based SystemsWindows 10 Version 1909 for 32-bit SystemsWindows 10 Version 1903 for 32-bit SystemsWindows 10 Version 1903 for ARM64-based SystemsWindows Server, version 1909 (Server Core installation)SMBv3
Affected versions
  • unspecified
Weaknesses (CWE)

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: 99.8%

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

Are you affected?

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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