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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 3 May 2022.
Windows Server 2008Operating system · Microsoft

CVE-2020-1040

CRITICAL · 9.0 CVSS v3.1 Published 2020-07-14
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
98/100
Remediation priority · Urgent
In the wild Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A remote code execution vulnerability exists in Hyper-V RemoteFX vGPU where the host server fails to properly validate input from an authenticated user on a guest operating system. An attacker with valid credentials on a guest VM can exploit this input validation flaw to execute arbitrary code on the underlying Hyper-V host with elevated privileges.

MitigationDisable the RemoteFX vGPU feature on affected Hyper-V hosts if not required, or apply Microsoft security updates. Implement network segmentation and restrict VM access to trusted users only.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Windows Server 2008Operating system
Affected:= r2
Windows Server 2012Operating system
Affected:all versions= r2
Windows Server 2016Operating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Windows Server version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to determine the installed Windows Server version
    Affected if The version matches Windows Server 2008 R2, 2012, 2012 R2, or 2016
  2. Verify Hyper-V role is installed
    Run 'Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V' in PowerShell, or check via Server Manager
    Affected if Hyper-V is installed and running
  3. Identify VMs with RemoteFX vGPU enabled
    Run 'Get-VMRemoteFx3DVideoAdapter -VMName *' to list all VMs and their RemoteFX adapter status, or inspect VM settings via Hyper-V Manager
    Affected if Any virtual machine has the RemoteFX vGPU adapter configured or enabled
  4. Confirm RemoteFX is actively used
    Run 'Get-VMRemoteFx3DVideoAdapter -VMName <VMName> | Select-Object Enabled' for each VM to check if the adapter is actively enabled
    Affected if RemoteFX3DVideoAdapter shows Enabled=True on any VM
  5. Check for presence of vGPU device
    Run 'Get-VM -Name * | Get-VMDevice | Where-Object {$_.DeviceId -like "*VGPU*"}' or inspect VM configuration XML for RemoteFX GPU hardware entries
    Affected if A RemoteFX vGPU device is assigned to any guest VM

The environment is affected if the host runs a vulnerable Windows Server version AND has RemoteFX vGPU enabled on one or more virtual machines.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch portal.msrc.microsoft.com →
Interim mitigation

Disable the RemoteFX vGPU feature on affected Hyper-V hosts if not required, or apply Microsoft security updates. Implement network segmentation and restrict VM access to trusted users only.

Recommended fix Moderate confidence

Microsoft ended support for Windows Server 2008 R2, 2012, and 2012 R2; migrate to Windows Server 2019 or Windows Server 2022 for continued security support

  1. Identify the specific Windows Server version and build running in your environment
  2. Check installed patches via Control Panel > Programs > View installed updates or run: Get-HotFix
  3. Apply the May 2020 security updates from Microsoft for your affected Windows Server version: For Windows Server 2016, install KB4558998 or subsequent monthly rollups; For Windows Server 2012 R2, install KB4558997; For Windows Server 2012, install KB4558993; For Windows Server 2008 R2, install KB4558994
  4. Alternatively, run Windows Update and install all pending security updates
  5. After patching, verify the RemoteFX vGPU component is updated by checking the Hyper-V host for the installed version of vmcompute.exe or RemoteFX components
  6. Consider disabling RemoteFX vGPU if not required: Open Hyper-V Manager, go to the VM Settings > Add Hardware, ensure RemoteFX 3D Adapter is not present; For existing deployments, remove RemoteFX 3D Adapter from VMs
  7. Restart the Hyper-V host after applying updates
Caveat RemoteFX is deprecated technology; ensure GPU-intensive workloads have alternative solutions before removing RemoteFX; some legacy applications may depend on vGPU capabilities

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows Server 2008 Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-1040 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data