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Windows CVE-2026-21247

HIGH
Improper Input Validation (CWE-20)
2026-02-10 secure@microsoft.com
7.3
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
7.3 HIGH
AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Analysis Generated
Mar 12, 2026 - 22:02 vuln.today
CVE Published
Feb 10, 2026 - 18:16 nvd
HIGH 7.3

DescriptionCVE.org

Improper input validation in Windows Hyper-V allows an authorized attacker to execute code locally.

AnalysisAI

Improper input validation in Windows Hyper-V allows an authorized attacker to execute code locally. [CVSS 7.3 HIGH]

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  • Attack chain visualization
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
Local user logs into Windows system
Exploit
Crafts malicious input for Hyper-V component
Execution
Triggers improper input validation flaw
Impact
Executes arbitrary code with elevated privileges

Vulnerability AssessmentAI

Exploitation Requires local system access with low-privilege user account and user interaction (UI:R). … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment CVSS 7.3 (HIGH). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario An attacker could exploit this vulnerability to compromise the affected system.
Remediation Monitor vendor advisories for a patch. Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours: Identify and inventory all systems running Hyper-V, assess exposure in production environments, and establish incident response readiness. …

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Threat intelligence, references, and detailed analysis are available after sign-in.

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CVE-2026-21247 vulnerability details – vuln.today

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