CVE intelligence

CVE-2026-40402

Vulnerability intelligence

Published May 12, 2026Sources checked Nov 11, 2026

9.3CRITICALCVSS out of 10

What this means

Review the available evidence

CVE-2026-40402 and is rated Critical severity with a CVSS score of 9.3. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: May 12, 2026

Vendor remediation details

Install KB5087545. Install KB5087424. Install KB5087420. Install KB5093998.

Vendor-listed releases

10.0.20348.5139
10.0.20348.5074
10.0.22631.7079
10.0.22631.7219

CISA KEVNot listedBased on the latest collected catalog

EPSS0.3%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-40402?

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

Source: NVD