NULL pointer dereference in Microsoft Windows and Windows Server - CVE-2026-24293

Vulnerability identifier: #VU123751

CSH Severity: Low

CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-24293

CWE-ID: CWE-476

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local suer to escalate privileges on the system.

The vulnerability exists due to a NULL pointer dereference error in Windows Ancillary Function Driver for WinSock. A local user can pass specially crafted data to the application and gain elevated privileges on the target system.

Microsoft Windows
Windows Server

Install updates from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7058, 10 22H2 10.0.19045.7058, 10 1607 10.0.14393.8957, 11 23H2 10.0.22631.6783, 11 24H2 10.0.26100.7979, 11 24H2 10.0.26100.8037
Windows Server - addressed in versions 2022 23H2 10.0.25398.2207, 2022 10.0.20348.4830, 2022 10.0.20348.4893, 2025 10.0.26100.32463, 2025 10.0.26100.32522

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-24293

• Multiple vulnerabilities in Microsoft Windows Ancillary Function Driver for WinSock