CVE-2026-20921

Published Jan 13, 2026

Last updated 12 days ago

Overview

Description
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to elevate privileges over a network.
Source
secure@microsoft.com
NVD status
Modified
Products
windows_10_1607, windows_10_1809, windows_10_21h2, windows_10_22h2, windows_11_23h2, windows_11_24h2, windows_11_25h2, windows_server_2008, windows_server_2012, windows_server_2016, windows_server_2019, windows_server_2022, windows_server_2022_23h2, windows_server_2025

Risk scores

CVSS 3.1

Type
Secondary
Base score
7.5
Impact score
5.9
Exploitability score
1.6
Vector string
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

Weaknesses

secure@microsoft.com
CWE-362

Social media

Hype score
Not currently trending

Configurations