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CVE-2026-50399 Microsoft CVE debrief

CVE-2026-50399 is an out-of-bounds read vulnerability in the Windows Kernel. An authorized attacker can exploit this vulnerability to elevate privileges locally. The vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. This vulnerability affects multiple versions of Windows, including Windows 10, Windows 11, and Windows Server. System administrators and users of Windows 10, Windows 11, and Windows Server should be aware of this vulnerability and take necessary actions to mitigate it.

Vendor
Microsoft
Product
Windows 10 Version 21H2
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-14
Original CVE updated
2026-07-21
Advisory published
2026-07-14
Advisory updated
2026-07-21

Who should care

System administrators and users of Windows 10, Windows 11, and Windows Server should be aware of this vulnerability and take necessary actions to mitigate it. This includes reviewing the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Technical summary

The vulnerability is caused by an out-of-bounds read in the Windows Kernel. This allows an authorized attacker to elevate privileges locally. The vulnerability affects multiple versions of Windows, including Windows 10, Windows 11, and Windows Server. System administrators and users should be aware of this vulnerability and take necessary actions to mitigate it.

Defensive priority

High

Recommended defensive actions

  • Apply patches released by Microsoft
  • Ensure Windows is up-to-date
  • Monitor system logs for suspicious activity
  • Implement additional security measures to prevent local privilege escalation
  • Review compensating controls for exposed systems while remediation is scheduled and verified

Evidence notes

The CVE record was published on 2026-07-14T18:17:42.147Z and was last modified on 2026-07-21T12:14:07.167Z. The NVD entry is currently Analyzed. This vulnerability affects multiple versions of Windows, including Windows 10, Windows 11, and Windows Server. The vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. System administrators and users should be aware of this vulnerability and take necessary actions to mitigate it.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-14T18:17:42.147Z and has not been modified since then. The NVD entry is currently Analyzed.