CVE-2026-21251
Cluster Client Failover (CCF) Elevation of Privilege Vulnerability
CVSS Score
7.8
EPSS Score
0.0%
EPSS Percentile
10th
Use after free in Windows Cluster Client Failover allows an authorized attacker to elevate privileges locally.
| Vendor | microsoft |
| Product | windows server 2016 |
| Ecosystems | |
| Industries | TechnologyEnterprise |
| Published | Feb 10, 2026 |
| Last Updated | Apr 10, 2026 |
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CVSS v3 Breakdown
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 Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
Affected Versions
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