---
id: "CVE-2020-0796"
kind: "vulnerability"
aliases: ["CVE-2020-0796"]
title: "Microsoft SMBv3: Microsoft SMBv3 Remote Code Execution Vulnerability"
severity: "critical"
cvss: 10.0
epss: 0.9981
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft SMBv3", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "file-servers", "infrastructure", "ransomware", "smb", "windows"]
not_affected_if: ["unknown"]
published_at: "2020-03-12T16:15:15+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-0796", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2020-0796", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-0796", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Microsoft SMBv3: Microsoft SMBv3 Remote Code Execution Vulnerability

Microsoft's SMBv3 file-sharing protocol mishandles certain requests, so a remote attacker can run code on the target server or client. CISA lists it as actively exploited in the wild, and EPSS puts exploitation likelihood at 0.998.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Microsoft SMBv3 affected ? fixed ?

## Fix

Apply the Microsoft updates for CVE-2020-0796 per vendor instructions (CISA required action).

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-0796
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2020-0796
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2020-0796

## From the sources

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.

CISA required action: Apply updates per vendor instructions.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_