CVE-2026-88102: Microsoft Failover Cluster Remote Code Execution Vulnerability

Overview

Severity

Critical (CVSS 9.8)

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Category

Remote Code Execution

Exploit Status

Not Exploited

Exploitation Likelihood

Unlikely

Patch Tuesday

2026-Oct

Released

2026-10-13

Description

Use after free in Windows Failover Cluster allows an unauthorized attacker to execute code over a network.

FAQ

How could an attacker exploit this vulnerability? An unauthenticated attacker could exploit this vulnerability by sending a specially crafted packet to an affected service over the network. Successful exploitation could allow the attacker to execute code on the target system. No authentication or user interaction is required..

Affected Products (6)

Windows

• Windows Server 2019
• Windows Server 2019 (Server Core installation)
• Windows Server 2022
• Windows Server 2022 (Server Core installation)
• Windows Server 2025
• Windows Server 2025 (Server Core installation)

Security Updates (3)

• 5126651
• 5126655
• 5126646

Acknowledgments

41ae55e9310ff27fa6f26af4727e5590

Revision History

• 2026-10-13: Information published.