Untrusted Pointer Dereference in Microsoft Windows and Windows Server - CVE-2026-105559

Vulnerability identifier: #VU164679

CSH Severity: Low

CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-105559

CWE-ID: CWE-822

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote user to cause a denial of service in Windows Active Directory.

The vulnerability exists due to an untrusted pointer dereference in Windows Active Directory when handling network requests. A remote user can send specially crafted requests to trigger an invalid memory access and cause a denial of service.

Microsoft Windows
Windows Server

Install security update from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7846, 10 22H2 10.0.19045.7846, 10 1607 10.0.14393.9688, 10 1809 10.0.17763.9487, 11 23H2 10.0.22631.7711, 11 24H2 10.0.26100.9911, 11 24H2 10.0.26100.9974, 11 25H2 10.0.26200.9911, 11 25H2 10.0.26200.9974, 11 26H1 10.0.28000.3501
Windows Server - addressed in versions 2016 10.0.14393.9688, 2019 10.0.17763.9487, 2022 10.0.20348.5870, 2025 10.0.26100.33730, 2025 10.0.26100.33822

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-105559
• https://support.microsoft.com/help/5132061

• Multiple vulnerabilities in Microsoft Windows