CVE-2026-21251

HIGH

Windows Cluster Client Failover - Privilege Escalation

Title source: llm
STIX 2.1

Description

Use after free in Windows Cluster Client Failover allows an authorized attacker to elevate privileges locally.

References (1)

Core 1
Core References

Scores

CVSS v3 7.8
EPSS 0.0004
EPSS Percentile 11.8%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/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-416
Status published
Products (13)
Microsoft/Windows Server 2016 10.0.14393.0 - 10.0.14393.8868
Microsoft/Windows Server 2016 (Server Core installation) 10.0.14393.0 - 10.0.14393.8868
Microsoft/Windows Server 2019 10.0.17763.0 - 10.0.17763.8389
Microsoft/Windows Server 2019 (Server Core installation) 10.0.17763.0 - 10.0.17763.8389
Microsoft/Windows Server 2022 10.0.20348.0 - 10.0.20348.4773
Microsoft/Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.0 - 10.0.25398.2149
Microsoft/Windows Server 2025 10.0.26100.0 - 10.0.26100.32370
Microsoft/Windows Server 2025 (Server Core installation) 10.0.26100.0 - 10.0.26100.32370
microsoft/windows_server_2016 < 10.0.14393.8868
microsoft/windows_server_2019 < 10.0.17763.8389
... and 3 more
Published Feb 10, 2026
Tracked Since Feb 18, 2026