Feb 2026: Cluster Client Failover (CCF) Elevation of Privilege Vulnerability
CVE-2026-21251 Published on February 10, 2026
Cluster Client Failover (CCF) Elevation of Privilege Vulnerability
Use after free in Windows Cluster Client Failover allows an authorized attacker to elevate privileges locally.
Weakness Type
What is a Dangling pointer Vulnerability?
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
CVE-2026-21251 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-21251
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Affected Versions
Microsoft Windows Server 2016:- Version 10.0.14393.0 and below 10.0.14393.8868 is affected.
- Version 10.0.14393.0 and below 10.0.14393.8868 is affected.
- Version 10.0.17763.0 and below 10.0.17763.8389 is affected.
- Version 10.0.17763.0 and below 10.0.17763.8389 is affected.
- Version 10.0.20348.0 and below 10.0.20348.4773 is affected.
- Version 10.0.25398.0 and below 10.0.25398.2149 is affected.
- Version 10.0.26100.0 and below 10.0.26100.32370 is affected.
- Version 10.0.26100.0 and below 10.0.26100.32370 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.