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PatchSiren cyber security CVE debrief

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
2026-07-01
Advisory published
2026-06-09
Advisory updated
2026-07-01

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.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-45638 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-45638

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

  • CVE-2026-45638 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-45638

    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.