Buffer Over-Read in Windows Hyper-V

Executive Summary

CVE-2026-50485 is a buffer over-read vulnerability in Windows Hyper-V. This flaw occurs when the software reads more data from a buffer than is allocated, which can lead to unintended behavior.

An authorized attacker with high privileges (PR:H) can exploit this vulnerability over an adjacent network (AV:A). The attack does not require user interaction (UI:N) and can result in a denial of service (A:H), meaning it can crash or disrupt the affected Hyper-V service.

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Detection Guidance

Detection requires monitoring Hyper-V network traffic for abnormal patterns or crashes. Check Windows Event Logs for Hyper-V-related errors or service disruptions. Use network monitoring tools to inspect adjacent network segments for unusual traffic targeting Hyper-V hosts.

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Impact Analysis

If you are using Windows Hyper-V, this vulnerability could impact you in the following ways:

• Denial of Service (DoS): An attacker with authorized access to an adjacent network could exploit this flaw to crash or disrupt the Hyper-V service, leading to downtime for virtual machines or hosted services.
• Limited Scope: The attack requires adjacent network access and high privileges, reducing the risk of widespread exploitation but still posing a threat in shared or multi-tenant environments.

No data theft or code execution is indicated, so the primary risk is service disruption.

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Compliance Impact

This vulnerability may impact compliance with standards and regulations in the following ways:

• GDPR: If the affected Hyper-V environment processes personal data of EU citizens, a denial of service could lead to availability issues, potentially violating GDPR's requirements for data availability and resilience (Article 32).
• HIPAA: For healthcare organizations, service disruption in Hyper-V could affect the availability of protected health information (PHI), potentially violating HIPAA's Security Rule, which mandates safeguards for electronic PHI.
• Other Standards: Compliance frameworks like ISO 27001 or NIST SP 800-53 emphasize system availability and resilience. A DoS vulnerability could indicate a failure to meet these requirements.

However, the specific impact depends on the environment and how critical Hyper-V is to your operations. Patching the vulnerability promptly would help maintain compliance.

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Mitigation Strategies

Apply the security update provided by Microsoft to address CVE-2026-50485. The update can be found on the Microsoft Update Guide for this vulnerability.

Ensure that only authorized users have access to the Hyper-V environment, as the vulnerability requires an authorized attacker.

Monitor adjacent networks for unusual activity that could indicate exploitation attempts.

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