CVE-2026-85939

Undergoing Analysis Undergoing Analysis - In Progress

Windows Kernel Security Feature Bypass via Weak Authentication

Publication date: 2026-10-13

Last updated on: 2026-10-16

Assigner: Microsoft Corporation

Description

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

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-10-13

Last Modified

2026-10-16

Generated

2026-10-19

AI Q&A

2026-10-14

EPSS Evaluated

2026-10-18

NVD

CVE-2026-85939

EUVD

EUVD-2026-99635

Affected Vendors & Products

Vendor	Product	Version / Range
Microsoft	Windows	10 Version 1607 10.0.14393.0
Microsoft	Windows	10 Version 1809 10.0.17763.0
Microsoft	Windows	10 Version 21H2 10.0.19044.0
Microsoft	Windows	10 Version 22H2 10.0.19045.0
Microsoft	Windows	11 version 23H2 10.0.22631.0
Microsoft	Windows	11 Version 23H2 10.0.22631.0
Microsoft	Windows	11 Version 24H2 10.0.26100.0
Microsoft	Windows	11 Version 25H2 10.0.26200.0
Microsoft	Windows	11 version 26H1 10.0.28000.0
Microsoft	Windows	11 Version 26H2 10.0.26300.0
Microsoft	Windows	Server 2016 10.0.14393.0
Microsoft	Windows	Server 2016 (Server Core installation) 10.0.14393.0
Microsoft	Windows	Server 2019 10.0.17763.0
Microsoft	Windows	Server 2019 (Server Core installation) 10.0.17763.0
Microsoft	Windows	Server 2022 10.0.20348.0
Microsoft	Windows	Server 2025 10.0.26100.0
Microsoft	Windows	Server 2025 (Server Core installation) 10.0.26100.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-1390	The product uses an authentication mechanism to restrict access to specific users or identities, but the mechanism does not sufficiently prove that the claimed identity is correct.

Attack-Flow Graph

Executive Summary

This vulnerability involves weak authentication in the Windows Kernel that allows an authorized attacker to bypass a security feature over a network. It is classified as a security feature bypass with a maximum severity rated as Important.

Impact Analysis

An attacker could exploit this to bypass security controls in Windows systems, potentially gaining unauthorized access or executing actions they should not be able to perform. This could lead to data breaches or system compromise.

Compliance Impact

This vulnerability may violate compliance requirements that mandate strong authentication and security feature integrity, such as GDPR's data protection measures or HIPAA's safeguards for protected health information.

Mitigation Strategies

Apply the latest security updates from Microsoft to patch the Windows Kernel authentication weakness. Monitor Microsoft's update guide for specific patches and install them as soon as possible.

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