This vulnerability (CVE-2026-20860) is classified as CWE-843 (Access of Resource Using Incompatible Type, or type confusion) affecting Windows 10 Version 1607 (build 10.0.14393.0). It exists in the Windows Ancillary Function Driver for WinSock and enables an authorized local attacker to elevate privileges on the affected system. The CVSS v3.1 base score is 7.8, indicating high severity, with attack vector local, low attack complexity, and no user interaction required. Microsoft has released an official fix for this vulnerability as documented in their security update guide.

Successful exploitation allows an authorized local attacker to elevate privileges, potentially gaining higher system rights than intended. This can lead to full system compromise depending on the privileges gained. The vulnerability affects confidentiality, integrity, and availability (all rated high impact).

An official fix is available from Microsoft. Users and administrators should apply the security update provided by Microsoft for Windows 10 Version 1607 (build 10.0.14393.0) as soon as possible to remediate this vulnerability. Refer to the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20860 for update details and installation instructions.