CVE-2026-34344

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Access of resource using incompatible type ('type confusion') in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

Affected

Microsoft · Windows 10 Version 1607 · Windows 10 Version 1809 · Windows 10 Version 21H2 · Windows 10 Version 22H2 · Windows 11 version 23H2 · Windows 11 Version 23H2

CVSS v3.1 MICROSOFT

7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

0.33% chance of exploitation in the next 30 days, 25th percentile

Published

2026-05-12

Updated

2026-08-10

Proof-of-concept exploits (1)

• nhh9905/CVE-2026-343442★ · 2026-08-21

Security advisories

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34344

References

• CVE Record
• NVD entry

Related

• CVE-2022-37969
• CVE-2023-36802
• CVE-2026-62735