CVE-2026-21251

CWE-416 — Use After Free5 documents5 sources
Severity
7.8HIGH
EPSS
0.0%
top 90.37%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
8
Microsoft Windows Server 2016Microsoft Windows Server 2016 (server Core Installation)Microsoft Windows Server 2019+5 more
Timeline
PublishedFeb 10

Description

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

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitability: 1.8 | Impact: 5.9

Affected Packages8 packages

▶NVDmicrosoft/windows< 10.0.14393.8868+4
▶CVEListV5microsoft/windows_server_201610.0.14393.0 — 10.0.14393.8868
▶CVEListV5microsoft/windows_server_201910.0.17763.0 — 10.0.17763.8389
▶CVEListV5microsoft/windows_server_202210.0.20348.0 — 10.0.20348.4773
▶CVEListV5microsoft/windows_server_202510.0.26100.0 — 10.0.26100.32370

🔴Vulnerability Details

2
CVEList
Cluster Client Failover (CCF) Elevation of Privilege Vulnerability↗2026-02-10
▶
GHSA
GHSA-6q2h-rrfg-fm75: Use after free in Windows Cluster Client Failover allows an authorized attacker to elevate privileges locally↗2026-02-10
▶

📋Vendor Advisories

1
Microsoft
Cluster Client Failover (CCF) Elevation of Privilege Vulnerability↗2026-02-10
▶

🕵️Threat Intelligence

1
Wiz
CVE-2026-21251 Impact, Exploitability, and Mitigation Steps | Wiz↗
▶
CVE-2026-21251 (HIGH CVSS 7.8) | Use after free in Windows Cluster C | cvebase.io