CVE-2026-20921 HIGH

CVE-2026-20921: Windows SMB Server Elevation of Privilege Vulnerability

Vendor Microsoft
Product Windows 10 Version 1607
Weakness CWE-362
Published January 13, 2026
Last update May 26, 2026
View on NVD All CVEs

CVSS base score

7.5/10
Attack vector Network
Attack complexity High
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

What the vulnerability does

01Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to elevate privileges over a network.

Key dates

02Disclosure timeline

January 13, 2026 CVE published
May 26, 2026 Record updated