---
id: CVE-2026-85858
title: >-
  Out-of-bounds read in Windows Win32 Kernel Subsystem allows an authorized
  attacker to elevate privileges locally.
summary: >-
  Out-of-bounds read in Windows Win32 Kernel Subsystem allows an authorized
  attacker to elevate privileges locally.
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H'
cwe:
  - CWE-125
published: '2026-10-13'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T21:19:28.407'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85858'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85858'
    label: secure@microsoft.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-13T19:43:29.183Z'
vendor: Microsoft
product: Windows 11 version 23H2
affected:
  - windows_11_version_23h2 >= 10.0.22631.0 < 10.0.22631.7652
  - windows_11_version_23h2 >= 10.0.22631.0 < 10.0.22631.7652
  - windows_11_version_24h2 >= 10.0.26100.0 < 10.0.26100.9711
  - windows_11_version_25h2 >= 10.0.26200.0 < 10.0.26200.9711
  - windows_11_version_26h1 >= 10.0.28000.0 < 10.0.28000.3231
  - windows_11_version_26h2 >= 10.0.26300.0 < 10.0.26300.9711
  - windows_server_2022 >= 10.0.20348.0 < 10.0.20348.5761
  - windows_server_2025 >= 10.0.26100.0 < 10.0.26100.33650
  - >-
    windows_server_2025_server_core_installation >= 10.0.26100.0 <
    10.0.26100.33650
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-13T20:06:41.893426Z'
epss: 0.00252
epssPercentile: 0.16552
---

## Overview

Out-of-bounds read in Windows Win32 Kernel Subsystem allows an authorized attacker to elevate privileges locally.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.