CVE-2026-21251

EUVD-2026-7326
Use after free in Windows Cluster Client Failover allows an authorized attacker to elevate privileges locally.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
7.8 HIGH
LOCAL
LOW
LOW
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
microsoftCNA
7.8 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Base Score
CVSS 3.x
EPSS Score
Percentile: 4%
Affected Products (NVD)
VendorProductVersion
microsoftwindows_server_2016
𝑥
< 10.0.14393.8868
microsoftwindows_server_2019
𝑥
< 10.0.17763.8389
microsoftwindows_server_2022
𝑥
< 10.0.20348.4711
microsoftwindows_server_2022_23h2
𝑥
< 10.0.25398.2149
microsoftwindows_server_2025
𝑥
< 10.0.26100.32313
𝑥
= Vulnerable software versions
Windows Releases
Platform
Version
Windows Server 2016
Server Core
KB5075999
Standard
KB5075999
Windows Server 2019
Server Core
KB5075904
Standard
KB5075904
Windows Server 2022
23H2 Server Core
KB5075897
Server Core
KB5075943
Standard
KB5075943
Windows Server 2025
Server Core
KB5075942
Standard
KB5075942
Common Weakness Enumeration
References
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21251