What is CVE-2026-40402?

CVE-2026-40402 is a security advisory published by Microsoft Security Response Center (MSRC) with Critical severity. Windows Hyper-V Elevation of Privilege Vulnerability

Which CVE IDs does CVE-2026-40402 cover?

CVE-2026-40402 covers the following CVE IDs: CVE-2026-40402. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of CVE-2026-40402?

CVE-2026-40402 has a CVSS v3 base score of 9.3, published by Microsoft Security Response Center (MSRC).

Which products are affected by CVE-2026-40402?

CVE-2026-40402 affects 4 products, including: Windows 11 Version 23H2 for ARM64-based Systems; Windows 11 Version 23H2 for x64-based Systems; Windows Server 2022; Windows Server 2022 (Server Core installation).

CVE-2026-40402CriticalCVSS 9.3

Windows Hyper-V Elevation of Privilege Vulnerability

Vendor

Microsoft Security Response Center (MSRC)

Published

May 22, 2026

Last Modified

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🔗 CVE IDs covered (1)

CVE-2026-40402 →

📋 Description

Use after free in Windows Hyper-V allows an unauthorized attacker to elevate privileges locally.

🎯 Affected products4

Windows 11 Version 23H2 for ARM64-based Systems
Windows 11 Version 23H2 for x64-based Systems
Windows Server 2022
Windows Server 2022 (Server Core installation)

✅ Remediation

KB5087545 (Security Update) — fixed build 10.0.20348.5139 KB5087424 (Security Hotpatch Update) — fixed build 10.0.20348.5074 KB5087420 (Security Update) — fixed build 10.0.22631.7079 KB5093998 (Security Update) — fixed build 10.0.22631.7219

🔗 References (9)

advisoryhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40402
patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5087545
referencehttps://support.microsoft.com/help/5087545
patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5087424
referencehttps://support.microsoft.com/help/5087424
patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5087420
referencehttps://support.microsoft.com/help/5087420
patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5093998
referencehttps://support.microsoft.com/help/5093998