CVE-2020-1040 Microsoft Hyper-V RemoteFX vGPU Remote Code Execution Vulnerability
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.
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 3 Nov 2021.
- Rated Critical severity (CVSS 9.0, scored by CISA).
- It has been in the catalogue for 1,829 days. Systems still unpatched now have almost certainly been scanned for it.
What It Is
A remote code execution vulnerability exists when Hyper-V RemoteFX vGPU on a host server fails to properly validate input from an authenticated user on a guest operating system, aka 'Hyper-V RemoteFX vGPU Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2020-1032, CVE-2020-1036, CVE-2020-1041, CVE-2020-1042, CVE-2020-1043.
Affected Versions
| Product | Versions |
|---|---|
| Microsoft Windows Server | 2016 2016 (Core installation) 2008 R2 for x64-based Systems Service Pack 1 2008 R2 for x64-based Systems Service Pack 1 (Core installation) 2012 2012 (Core installation) |
From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for Microsoft Hyper-V RemoteFX. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
- 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
Vendor Advisories
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
Not Sure If You Are Exposed?
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