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CVE-2026-50349 Microsoft CVE debrief

CVE-2026-50349 is a high-severity vulnerability in the Windows Ancillary Function Driver for WinSock, allowing an authorized attacker to elevate privileges locally due to a race condition. The CVE record was published on 2026-09-08T18:17:38.537Z and was last modified on 2026-09-17T18:38:04.197Z. The NVD entry is currently Analyzed. This vulnerability has significant implications for defenders responsible for Windows systems, particularly those with high-risk exposure. An executive overview indicates that the vulnerability allows local privilege escalation, and defenders should prioritize patching, especially for high-risk systems, and verify system configurations to prevent or to  

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-09-17
Advisory published
2026-09-08
Advisory updated
2026-09-17

Who should care

Defenders responsible for Windows systems, especially those with high-risk exposure, should assess their systems for potential vulnerability and apply patches or compensating controls as needed.

Why it matters

CVE-2026-50349 is a high-severity vulnerability in the Windows Ancillary Function Driver for WinSock that allows local privilege escalation. Defenders should prioritize patching, especially for high-risk systems, and verify system configurations to prevent exploitation.

  • Local privilege escalation is possible, allowing attackers to gain elevated access.
  • Successful exploitation requires local access and specific conditions to be met.
  • Patching is necessary to prevent exploitation, especially on high-risk systems.
  • Verification of system configurations and compensating controls may be necessary for unpatched systems.

Technical summary

The vulnerability is caused by a race condition in the Windows Ancillary Function Driver for WinSock. An authorized attacker can exploit this vulnerability to elevate privileges locally. The vulnerability has a CVSS score of 7 and is classified as HIGH severity.

Defensive priority

Defenders should prioritize patching this vulnerability, especially for systems with high-risk exposure. This involves reviewing and applying the vendor's security update.

Recommended defensive actions

  • Apply the vendor's security update for the Windows Ancillary Function Driver for WinSock.
  • Review system configurations and ensure that only necessary services are running.
  • Monitor system logs for potential exploitation attempts.
  • Verify that affected systems are patched or have compensating controls in place.

Evidence notes

The CVE record and NVD detail provide information on the vulnerability, its impact, and affected systems. Microsoft's advisory offers guidance on patching.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-50349 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-50349

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

  • CVE-2026-50349 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-50349

    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.