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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
2026-07-22
Advisory published
2026-07-14
Advisory updated
2026-07-22

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.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-50399 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-50399

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-50399 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-50399

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.