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CVE-2026-50312 Microsoft CVE debrief

CVE-2026-50312 is a Use after free vulnerability in Windows Ancillary Function Driver for WinSock. An authorized attacker can exploit this vulnerability locally to elevate privileges. This vulnerability has a CVSS score of 4.7 and a severity rating of MEDIUM. System administrators and users of Windows operating systems should be aware of this vulnerability and apply patches as available. The vulnerability allows an attacker to exploit the Windows Ancillary Function Driver for WinSock, potentially leading to privilege escalation.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
MEDIUM 4.7
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 operating systems should be aware of this vulnerability and apply patches as available. This vulnerability has a CVSS score of 4.7 and a severity rating of MEDIUM, indicating a moderate level of risk. Affected operators and security teams should review official advisories and take necessary precautions to mitigate this vulnerability.

Technical summary

The vulnerability is a Use after free issue in the Windows Ancillary Function Driver for WinSock. This could allow an authorized attacker to elevate privileges locally. The CVSS score for this vulnerability is 4.7, with a severity rating of MEDIUM. The vulnerability affects Windows operating systems and requires local access for exploitation.

Defensive priority

Apply patches as available; monitor system logs for suspicious activity; conduct regular vulnerability assessments

Recommended defensive actions

  • Apply patches as available
  • Monitor system logs for suspicious activity
  • Conduct regular vulnerability assessments
  • Review compensating controls for exposed systems
  • Check relevant monitoring, detection, and logs for exposed assets

Evidence notes

The CVE record was published on 2026-07-14T18:17:29.503Z and was last modified on 2026-07-16T19:48:07.280Z. The NVD entry is currently Analyzed. This vulnerability affects Windows Ancillary Function Driver for WinSock, and its exploitation requires local access. The CVSS score for this vulnerability is 4.7, indicating a MEDIUM severity level. To verify and mitigate this vulnerability, defenders should review official advisories and apply patches as available.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-50312 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-50312

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

  • CVE-2026-50312 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-50312

    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.