CVE-2026-20921

HIGH

Windows SMB Server - Privilege Escalation

Title source: llm
STIX 2.1

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.

References (1)

Scores

CVSS v3 7.5
EPSS 0.0005
EPSS Percentile 16.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-362
Status published
Products (40)
Microsoft/Windows 10 Version 1607 10.0.14393.0 - 10.0.14393.8783
Microsoft/Windows 10 Version 1809 10.0.17763.0 - 10.0.17763.8276
Microsoft/Windows 10 Version 21H2 10.0.19044.0 - 10.0.19044.6809
Microsoft/Windows 10 Version 22H2 10.0.19045.0 - 10.0.19045.6809
Microsoft/Windows 11 version 22H3 10.0.22631.0 - 10.0.22631.6491
Microsoft/Windows 11 Version 23H2 10.0.22631.0 - 10.0.22631.6491
Microsoft/Windows 11 Version 24H2 10.0.26100.0 - 10.0.26100.7623
Microsoft/Windows 11 Version 25H2 10.0.26200.0 - 10.0.26200.7623
Microsoft/Windows Server 2008 R2 Service Pack 1 6.1.7601.0 - 6.1.7601.28117
Microsoft/Windows Server 2008 R2 Service Pack 1 (Server Core installation) 6.1.7601.0 - 6.1.7601.28117
... and 30 more
Published Jan 13, 2026
Tracked Since Feb 18, 2026