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Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

PUBLISHED Reserved 2026-03-26 | Published 2026-05-12 | Updated 2026-05-20 | Assigner microsoft




HIGH: 7.0CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Problem types

CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CWE-416: Use After Free

Product status

10.0.14393.0 (custom) before 10.0.14393.9140
affected

10.0.17763.0 (custom) before 10.0.17763.8755
affected

10.0.19044.0 (custom) before 10.0.19044.7291
affected

10.0.19045.0 (custom) before 10.0.19045.7291
affected

10.0.22631.0 (custom) before 10.0.22631.7079
affected

10.0.22631.0 (custom) before 10.0.22631.7079
affected

10.0.26100.0 (custom) before 10.0.26100.8457
affected

10.0.26200.0 (custom) before 10.0.26200.8457
affected

10.0.28000.0 (custom) before 10.0.28000.2113
affected

10.0.14393.0 (custom) before 10.0.14393.9140
affected

10.0.14393.0 (custom) before 10.0.14393.9140
affected

10.0.17763.0 (custom) before 10.0.17763.8755
affected

10.0.17763.0 (custom) before 10.0.17763.8755
affected

10.0.20348.0 (custom) before 10.0.20348.5139
affected

10.0.25398.0 (custom) before 10.0.25398.2330
affected

10.0.26100.0 (custom) before 10.0.26100.32860
affected

10.0.26100.0 (custom) before 10.0.26100.32860
affected

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34345 (Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability) vendor-advisory patch

cve.org (CVE-2026-34345)

nvd.nist.gov (CVE-2026-34345)

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