---
id: CVE-2026-26174
title: >-
  Concurrent execution using shared resource with improper synchronization
  ('race condition') in Windows Server Update Service allows an authorized
  attacker to elevate privileges locally.
summary: >-
  Concurrent execution using shared resource with improper synchronization
  ('race condition') in Windows Server Update Service allows an authorized
  attacker to elevate privileges locally.
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-362
  - CWE-416
vendor: microsoft
product: windows_10_1607
affected:
  - windows_10_1607 < 10.0.14393.9060
  - windows_10_1809 < 10.0.17763.8644
  - windows_10_21h2 < 10.0.19044.7184
  - windows_10_22h2 < 10.0.19045.7184
  - windows_11_23h2 < 10.0.22631.6936
  - windows_11_24h2 < 10.0.26100.8246
  - windows_11_25h2 < 10.0.26200.8246
  - windows_11_26h1 < 10.0.28000.1836
  - windows_server_2012
  - windows_server_2012 = r2
  - windows_server_2016 < 10.0.14393.9060
  - windows_server_2019 < 10.0.17763.8644
  - windows_server_2022 < 10.0.20348.5020
  - windows_server_2022_23h2 < 10.0.25398.2274
  - windows_server_2025 < 10.0.26100.32690
patched:
  - windows_10_1607 10.0.14393.9060
  - windows_10_1809 10.0.17763.8644
  - windows_10_21h2 10.0.19044.7184
  - windows_10_22h2 10.0.19045.7184
  - windows_11_23h2 10.0.22631.6936
  - windows_11_24h2 10.0.26100.8246
  - windows_11_25h2 10.0.26200.8246
  - windows_11_26h1 10.0.28000.1836
  - windows_server_2016 10.0.14393.9060
  - windows_server_2019 10.0.17763.8644
  - windows_server_2022 10.0.20348.5020
  - windows_server_2022_23h2 10.0.25398.2274
  - windows_server_2025 10.0.26100.32690
published: '2026-04-14'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T18:17:11.480'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-26174'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26174'
    label: secure@microsoft.com
tags:
  - nvd
  - cve.org
epss: 0.00202
epssPercentile: 0.08947
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-04-09T00:00:00+00:00'
ingestedAt: '2026-09-25T18:14:20.406Z'
---

## Overview

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Server Update Service allows an authorized attacker to elevate privileges locally.

## Affected

- `windows_10_1607 < 10.0.14393.9060`
- `windows_10_1809 < 10.0.17763.8644`
- `windows_10_21h2 < 10.0.19044.7184`
- `windows_10_22h2 < 10.0.19045.7184`
- `windows_11_23h2 < 10.0.22631.6936`
- `windows_11_24h2 < 10.0.26100.8246`
- `windows_11_25h2 < 10.0.26200.8246`
- `windows_11_26h1 < 10.0.28000.1836`
- `windows_server_2012`
- `windows_server_2012 = r2`
- `windows_server_2016 < 10.0.14393.9060`
- `windows_server_2019 < 10.0.17763.8644`
- `windows_server_2022 < 10.0.20348.5020`
- `windows_server_2022_23h2 < 10.0.25398.2274`
- `windows_server_2025 < 10.0.26100.32690`

## Remediation

Upgrade past the affected range:

- `windows_10_1607 10.0.14393.9060`
- `windows_10_1809 10.0.17763.8644`
- `windows_10_21h2 10.0.19044.7184`
- `windows_10_22h2 10.0.19045.7184`
- `windows_11_23h2 10.0.22631.6936`
- `windows_11_24h2 10.0.26100.8246`
- `windows_11_25h2 10.0.26200.8246`
- `windows_11_26h1 10.0.28000.1836`
- `windows_server_2016 10.0.14393.9060`
- `windows_server_2019 10.0.17763.8644`
- `windows_server_2022 10.0.20348.5020`
- `windows_server_2022_23h2 10.0.25398.2274`
- `windows_server_2025 10.0.26100.32690`