---
id: "CVE-2020-1040"
kind: "vulnerability"
aliases: ["CVE-2020-1040"]
title: "Microsoft Hyper-V RemoteFX: Microsoft Hyper-V RemoteFX vGPU Remote Code Execution Vulnerability"
severity: "critical"
cvss: 9.0
epss: 0.07393
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft Hyper-V RemoteFX", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "hyper-v", "infrastructure", "virtualization", "windows-server"]
not_affected_if: ["no-hyper-v-remotefx", "remotefx-vgpu-disabled"]
published_at: "2020-07-14T23:15:11+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T21:57:34+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-1040", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2020-1040", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-1040", "first_seen_at": "2026-10-23T21:57:34+00:00"}]
---

# Microsoft Hyper-V RemoteFX: Microsoft Hyper-V RemoteFX vGPU Remote Code Execution Vulnerability

Microsoft Hyper-V RemoteFX vGPU mishandles input from an authenticated guest OS user, letting that guest run code on the Hyper-V host. Exploitation is listed by CISA as known to be used in the wild.

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

## Affected

- vendor:Microsoft Hyper-V RemoteFX affected ? fixed ?

## Fix

Apply the Microsoft update for CVE-2020-1040 per vendor instructions (CISA KEV required action); the specific KB or patched build is not given in the sources.

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-1040
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2020-1040
- 2026-10-23T21:57:34+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2020-1040

## From the sources

Microsoft Hyper-V RemoteFX vGPU contains an improper input validation vulnerability due to the host server failing to properly validate input from an authenticated user on a guest operating system. Successful exploitation allows for remote code execution on the host operating system.

CISA required action: Apply updates per vendor instructions.

---

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