CVE-2026-20926

Windows SMB Server Elevation of Privilege Vulnerability

CVE-2026-20926 is fixed in 29 products on 1 platform, first by KB5073722, released January 13, 2026. It is not reported as exploited. Patch Radar priority: High.

High

CVSS

7.5

Important

Exploitation

None reported

Exploitation Unlikely

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0080

56th percentile

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

Where it's fixed

Product	Fixed in	Fix	Released
Microsoft
Windows 10 Version 1607 for 32-bit Systems	14393.8783	KB5073722	Jan 13, 2026
Windows 10 Version 1607 for x64-based Systems	14393.8783	KB5073722	Jan 13, 2026
Windows 10 Version 1809 for 32-bit Systems	17763.8276	KB5073723	Jan 13, 2026
Windows 10 Version 1809 for x64-based Systems	17763.8276	KB5073723	Jan 13, 2026
Windows 10 Version 21H2 for 32-bit Systems		KB5073724	Jan 13, 2026
Windows 10 Version 21H2 for ARM64-based Systems		KB5073724	Jan 13, 2026
Windows 10 Version 21H2 for x64-based Systems		KB5073724	Jan 13, 2026
Windows 10 Version 22H2 for 32-bit Systems		KB5073724	Jan 13, 2026
Windows 10 Version 22H2 for ARM64-based Systems		KB5073724	Jan 13, 2026
Windows 10 Version 22H2 for x64-based Systems		KB5073724	Jan 13, 2026
Windows 11 Version 23H2 for ARM64-based Systems	22631.6491	KB5073455	Jan 13, 2026
Windows 11 Version 23H2 for x64-based Systems	22631.6491	KB5073455	Jan 13, 2026
Windows 11 Version 24H2 for ARM64-based Systems		KB5074109	Jan 13, 2026
Windows 11 Version 24H2 for x64-based Systems		KB5074109	Jan 13, 2026
Windows 11 Version 25H2 for ARM64-based Systems		KB5074109	Jan 13, 2026
Windows 11 Version 25H2 for x64-based Systems		KB5074109	Jan 13, 2026
Windows Server 2012		KB5073698	Jan 13, 2026
Windows Server 2012 (Server Core installation)		KB5073698	Jan 13, 2026
Windows Server 2012 R2		KB5073696	Jan 13, 2026
Windows Server 2012 R2 (Server Core installation)		KB5073696	Jan 13, 2026
Windows Server 2016	14393.8783	KB5073722	Jan 13, 2026
Windows Server 2016 (Server Core installation)	14393.8783	KB5073722	Jan 13, 2026
Windows Server 2019	17763.8276	KB5073723	Jan 13, 2026
Windows Server 2019 (Server Core installation)	17763.8276	KB5073723	Jan 13, 2026
Windows Server 2022	20348.4648	KB5073457	Jan 13, 2026
Windows Server 2022 (Server Core installation)	20348.4648	KB5073457	Jan 13, 2026
Windows Server 2022, 23H2 Edition (Server Core installation)	25398.2092	KB5073450	Jan 13, 2026
Windows Server 2025	26100.32230	KB5073379	Jan 13, 2026
Windows Server 2025 (Server Core installation)	26100.32230	KB5073379	Jan 13, 2026

Details

Published
January 13, 2026
Weakness
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20926

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