CVE-2026-85939: Windows Kernel Security Feature Bypass Vulnerability

Overview

Severity: Medium (CVSS 5.3)
CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C
Category: Security Feature Bypass
Exploit Status: Not Exploited
Exploitation Likelihood: Less Likely
Patch Tuesday: 2026-Oct
Released: 2026-10-13

Description

Weak authentication in Windows Kernel allows an authorized attacker to bypass a security feature over a network.

FAQ

According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? The target environment could be accidentally configured to allow the vulnerability.

Affected Products (28)

Windows

Windows 10 Version 1809 for 32-bit Systems
Windows 10 Version 1809 for x64-based Systems
Windows Server 2019
Windows Server 2019 (Server Core installation)
Windows Server 2022
Windows Server 2022 (Server Core installation)
Windows 10 Version 21H2 for 32-bit Systems
Windows 10 Version 21H2 for ARM64-based Systems
Windows 10 Version 21H2 for x64-based Systems
Windows Server 2025 (Server Core installation)
Windows 11 Version 25H2 for ARM64-based Systems
Windows 11 Version 25H2 for x64-based Systems
Windows 11 Version 23H2 for ARM64-based Systems
Windows 11 Version 23H2 for x64-based Systems
Windows 11 Version 24H2 for ARM64-based Systems
Windows 11 Version 24H2 for x64-based Systems
Windows Server 2025
Windows 11 version 26H1 for x64-based Systems
Windows 11 Version 26H1 for ARM64-based Systems
Windows 10 Version 1607 for 32-bit Systems
Windows 10 Version 1607 for x64-based Systems
Windows Server 2016
Windows Server 2016 (Server Core installation)
Windows 11 Version 26H2 for ARM64-based Systems
Windows 11 Version 26H2 for x64-based Systems

ESU

Windows 10 Version 22H2 for x64-based Systems
Windows 10 Version 22H2 for ARM64-based Systems
Windows 10 Version 22H2 for 32-bit Systems

Security Updates (8)

Acknowledgments

haowei yan

Revision History

2026-10-13: Information published.