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CVE-2026-50403 Microsoft CVE debrief

CVE-2026-50403 is a high-severity vulnerability in Windows Runtime that allows an authorized attacker to elevate privileges locally due to a race condition. The vulnerability has a CVSS score of 7 and is classified as HIGH. Microsoft has released a patch for this vulnerability, and users are advised to apply it as soon as possible. The vulnerability affects Windows 11 and Windows Server 2025 systems, and its exploitation could lead to unauthorized privilege escalation. System administrators should prioritize patching to mitigate the risk.

Vendor
Microsoft
Product
Windows 11 Version 24H2
CVSS
HIGH 7
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 11 and Windows Server 2025 should be aware of this vulnerability and take necessary precautions to mitigate the risk. Affected operators should prioritize patching and review compensating controls for exposed systems.

Technical summary

The vulnerability is caused by a race condition in Windows Runtime, which allows an authorized attacker to elevate privileges locally. The vulnerability has been analyzed by the NVD and has a CVSS vector of CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. The technical details are limited to publicly available information, and defenders should review the official advisory for specific technical guidance.

Defensive priority

High

Recommended defensive actions

  • Apply the patch released by Microsoft
  • Ensure that Windows 11 and Windows Server 2025 systems are up-to-date with the latest security patches
  • Monitor systems for suspicious activity
  • Implement additional security measures such as multi-factor authentication and least privilege access
  • Review compensating controls for exposed systems while remediation is scheduled and verified

Evidence notes

The vulnerability is documented in the NVD and has been analyzed by Microsoft. The CVE record was published on 2026-07-14T18:17:42.780Z and was last modified on 2026-07-20T17:41:42.603Z. The evidence is limited to publicly available information, and defenders should verify the affected scope and vendor guidance for specific deployments.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-50403 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-50403

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

  • CVE-2026-50403 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-50403

    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.