# CVE-2020-0796: Windows SMBv3 Client/Server Remote Code Execution Vulnerability

CVE-2020-0796 is fixed in 8 products on 1 platform, first by KB4551762, released March 12, 2020. It is being exploited: CISA added it to the Known Exploited Vulnerabilities catalog on February 10, 2022, with known ransomware use. Patch Radar priority: Patch now.

- Web page: https://patchblox.com/security/cve/CVE-2020-0796
- Priority: Patch now
- CVSS: 10.0 (Critical)
- EPSS: 0.9981
- CISA KEV: listed Feb 10, 2022, federal due date Aug 10, 2022, known ransomware use
- Exploited (vendor report): no
- Publicly disclosed: yes
- Vendor exploitability assessment: Exploitation More Likely
- Published: Mar 12, 2020
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-0796

## Description

<p>A remote code execution vulnerability exists in the way that the Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain requests. An attacker who successfully exploited the vulnerability could gain the ability to execute code on the target server or client.</p> <p>To exploit the vulnerability against a server, an unauthenticated attacker could send a specially crafted packet to a targeted SMBv3 server. To exploit the vulnerability against a client, an unauthenticated attacker would need to configure a malicious SMBv3 server and convince a user to connect to it.</p> <p>The security update addresses the vulnerability by correcting how the SMBv3 protocol handles these specially crafted requests.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Windows 10 Version 1903 for 32-bit Systems |  | [KB4551762](https://patchblox.com/security/data/fix/microsoft/kb4551762.md) | Mar 12, 2020 |
| Microsoft | Windows 10 Version 1903 for ARM64-based Systems |  | [KB4551762](https://patchblox.com/security/data/fix/microsoft/kb4551762.md) | Mar 12, 2020 |
| Microsoft | Windows 10 Version 1903 for x64-based Systems |  | [KB4551762](https://patchblox.com/security/data/fix/microsoft/kb4551762.md) | Mar 12, 2020 |
| Microsoft | Windows 10 Version 1909 for 32-bit Systems |  | [KB4551762](https://patchblox.com/security/data/fix/microsoft/kb4551762.md) | Mar 12, 2020 |
| Microsoft | Windows 10 Version 1909 for ARM64-based Systems |  | [KB4551762](https://patchblox.com/security/data/fix/microsoft/kb4551762.md) | Mar 12, 2020 |
| Microsoft | Windows 10 Version 1909 for x64-based Systems |  | [KB4551762](https://patchblox.com/security/data/fix/microsoft/kb4551762.md) | Mar 12, 2020 |
| Microsoft | Windows Server, version 1903 (Server Core installation) |  | [KB4551762](https://patchblox.com/security/data/fix/microsoft/kb4551762.md) | Mar 12, 2020 |
| Microsoft | Windows Server, version 1909 (Server Core installation) |  | [KB4551762](https://patchblox.com/security/data/fix/microsoft/kb4551762.md) | Mar 12, 2020 |

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Data as of 2026-11-07T18:46:35Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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