CVE-2026-21251 - Vulnerability Details - OpenCVE

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

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Vendors	Products
Microsoft	Windows Server 2016 Windows Server 2019 Windows Server 2022 Windows Server 2025 Windows Server 23h2

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References

Link	Providers
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21251

History

Tue, 10 Feb 2026 18:15:00 +0000

Type	Values Removed	Values Added
Description		Use after free in Windows Cluster Client Failover allows an authorized attacker to elevate privileges locally.
Title		Cluster Client Failover (CCF) Elevation of Privilege Vulnerability
First Time appeared		Microsoft Microsoft windows Server 2016 Microsoft windows Server 2019 Microsoft windows Server 2022 Microsoft windows Server 2025 Microsoft windows Server 23h2
Weaknesses		CWE-416
CPEs		cpe:2.3:o:microsoft:windows_server_2016:::::::: cpe:2.3:o:microsoft:windows_server_2019:::::::: cpe:2.3:o:microsoft:windows_server_2022:::::::: cpe:2.3:o:microsoft:windows_server_2025:::::::: cpe:2.3:o:microsoft:windows_server_23h2::::::::
Vendors & Products		Microsoft Microsoft windows Server 2016 Microsoft windows Server 2019 Microsoft windows Server 2022 Microsoft windows Server 2025 Microsoft windows Server 23h2
References		https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21251
Metrics		cvssV3_1 `{'score': 7.8, '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'}`

MITRE

Status: PUBLISHED

Assigner: microsoft

Published: 2026-02-10T17:51:40.939Z

Updated: 2026-02-10T18:58:26.253Z

Reserved: 2025-12-11T21:02:05.736Z

Link: CVE-2026-21251

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-02-10T18:16:26.840

Modified: 2026-02-10T18:16:26.840

Link: CVE-2026-21251

Redhat

No data.

OpenCVE Enrichment

No data.

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