Security Resilience

CVE-2020-1040

Microsoft Windows Server 2012 r2

CISA KEVActive ExploitationEUVD Exploited
Published
14 July 2020
Modified
29 October 2025
KEV Added
03 November 2021
Patch / advisory
CVSS Score v3.1 9.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS Score 0.074 94th percentile
Risk Priority 89 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2020-1040 is a critical-severity Improper Input Validation (CWE-20) vulnerability in Microsoft Windows Server 2012. Its CVSS base score is 9.0 (Critical).

Operationally, ranked in the top 6% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

A remote code execution vulnerability tracked as CVE-2020-1040 affects the Hyper-V RemoteFX vGPU component on a host server. The flaw stems from improper input validation (CWE-20) when the component processes data originating from an authenticated user on a guest operating system, allowing the issue to be triggered across virtual machine boundaries.

An attacker with an authenticated session inside a guest virtual machine can send specially crafted input over an adjacent network to the host, achieving arbitrary code execution with high impact to confidentiality, integrity, and availability. The CVSS 9.0 vector reflects low attack complexity, no user interaction, and a scope change that extends compromise from the guest to the host hypervisor.

Microsoft and NVIDIA security advisories provide patches and configuration guidance to address the vulnerability on affected Hyper-V hosts, while the CISA known exploited vulnerabilities catalog confirms active tracking of the issue for prioritized remediation.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

unique from CVE-2020-1032, CVE-2020-1036, CVE-2020-1041, CVE-2020-1042, CVE-2020-1043.

CWE(s)
KEV Date Added
03 November 2021

Related Threats

Threat-Actor AttributionAI

Microsoft Corp. (Salesforce / Slack engineer recruitment claims)
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APT3 (G0022)
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Winnti Group (G0044)
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menuPass (G0045)
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Leviathan (G0065)
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APT19 (G0073)
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APT41 (G0096)
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AnonOps
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CVEs Like This One

CVE-2020-1350Same product: Microsoft Windows Server 2008both on KEV
CVE-2023-36563Same product: Microsoft Windows Server 2008both on KEV
CVE-2025-32706Same product: Microsoft Windows Server 2008both on KEV
CVE-2012-0151Same product: Microsoft Windows Server 2008both on KEV
CVE-2023-36706Same product: Microsoft Windows Server 2008
CVE-2024-30040Same product: Microsoft Windows Server 2016both on KEV
CVE-2019-0604Same vendor: Microsoftboth on KEV
CVE-2021-36942Same product: Microsoft Windows Server 2008both on KEV
CVE-2026-32201Same vendor: Microsoftboth on KEV
CVE-2023-36761Same vendor: Microsoftboth on KEV

Affected Assets

microsoft
windows server 2008
r2
microsoft
windows server 2012
all versions, r2
microsoft
windows server 2016
all versions

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

blocks

A.8.25 mandates security requirements, secure coding guidelines, checkpoints, testing (incl. code scans) and developer training in the SDLC, which reaches a slice of input validation defects but leaves the majority (incomplete enforcement, second-order inputs, parser differentials, post-validation canonicalization) unaddressed as in the SA-3 and A.8.28 anchors.

blocks

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

blocks

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-20, a class-level weakness, and none of its children carries one either.

References