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CVE-2026-45638 Microsoft CVE debrief

CVE-2026-45638 is a use-after-free vulnerability in the Windows Ancillary Function Driver for WinSock. This vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. An authorized attacker can exploit this vulnerability to elevate privileges locally.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-06-11
Advisory published
2026-06-09
Advisory updated
2026-06-11

Who should care

Administrators and users of Windows operating systems should be aware of this vulnerability and take necessary precautions to mitigate the risk.

Technical summary

The vulnerability exists in the Windows Ancillary Function Driver for WinSock and is caused by a use-after-free error. This allows an authorized attacker to elevate privileges locally.

Defensive priority

High

Recommended defensive actions

  • Apply patches and updates from Microsoft as soon as possible.
  • Ensure that all Windows operating systems and related software are up-to-date.
  • Monitor system logs for suspicious activity.

Evidence notes

The CVE record and NVD detail pages provide additional information about this vulnerability.

Official resources

CVE-2026-45638 was published on 2026-06-09T17:17:30.587Z and modified on 2026-06-11T18:23:36.460Z.