CVE-2026-81963: CWE-59: Improper Link Resolution Before File Access ('Link Following') in Microsoft Windows 11 version 23H2

CVE-2026-81963 is a vulnerability classified under CWE-59 (Improper Link Resolution Before File Access) affecting the Windows Update Stack in Windows 11 version 23H2. It allows an authorized local attacker to elevate privileges by exploiting improper handling of symbolic links or similar link types before accessing files. The vulnerability affects multiple builds of Windows 11 23H2, specifically versions >=10.0.22631.0 and <10.0.22631.7582, >=10.0.26100.0 and <10.0.26100.9445, >=10.0.26200.0 and <10.0.26200.9445, >=10.0.28000.0 and <10.0.28000.2954, and >=10.0.26100.0 and <10.0.26100.33438. Microsoft has released an official fix for this vulnerability.

An authorized local attacker can exploit this vulnerability to elevate their privileges on the affected Windows 11 systems. The CVSS 3.1 base score is 7.8, indicating high severity with high impact on confidentiality, integrity, and availability. There are no known exploits in the wild currently.

An official fix is available from Microsoft. Users and administrators should apply the security updates provided by Microsoft for Windows 11 version 23H2 to remediate this vulnerability. Refer to the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81963 for update details and guidance.