Summary
Impact: Security Feature Bypass. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
Successful exploitation of this vulnerability requires an attacker to have a deep understanding of the system. Successful exploitation is not guaranteed and depends on a combination of factors that might include the environment, system configuration, and the presence of additional security measures.
What kind of security feature could be bypassed by successfully exploiting this vulnerability?
This Hyper-V vulnerability relates to a Virtual Machine Switch with virtual networking in Hyper-V Network Virtualization (HNV). It might be possible to bypass extended ACLs and other Windows security feature checks.
See Create Security Policies with Extended Port Access Control Lists for information about extended ACLs.
Security updates
10.0.17763.9376 — https://support.microsoft.com/help/5126651
10.0.20348.5761 — https://support.microsoft.com/help/5126655
10.0.19044.7807 — https://support.microsoft.com/help/5126657
10.0.26100.33650 — https://support.microsoft.com/help/5126646
10.0.26200.9711 — https://support.microsoft.com/help/5127648
10.0.22631.7652 — https://support.microsoft.com/help/5126653
10.0.28000.3231 — https://support.microsoft.com/help/5127646
10.0.14393.9612 — https://support.microsoft.com/help/5126868
Vulnerabilities 1
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Medium 4.2
Windows Hyper-V Security Feature Bypass Vulnerability
Incorrect authorization in Windows Hyper-V allows an authorized attacker to bypass a security feature over an adjacent network.
Revision history
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#1
Information published.
References
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CVE-2026-83766 Windows Hyper-V Security Feature Bypass Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83766
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss