CVE-2026-21251 HIGH

CVE-2026-21251: Cluster Client Failover (CCF) Elevation of Privilege Vulnerability

Vendor Microsoft
Product Windows Server 2016
Weakness CWE-416
Published February 10, 2026
Last update May 11, 2026
View on NVD All CVEs

CVSS base score

7.8/10
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

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

What the vulnerability does

01Description

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

Key dates

02Disclosure timeline

February 10, 2026 CVE published
May 11, 2026 Record updated