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Microsoft Security Response CenterCVE-2026-78444

Microsoft Failover Cluster Remote Code Execution Vulnerability

CriticalVendor CVSS 8.1 / 10 1 CVE Published Sep 8, 2026 at 7:00 AM UTC

Summary

Untrusted pointer dereference in Windows Failover Cluster allows an unauthorized attacker to execute code over a network.

Products covered

  • Windows 10 Version 1809 for 32-bit Systems

  • Windows 10 Version 1809 for x64-based Systems

  • Windows Server 2019

  • Windows Server 2019 (Server Core installation)

  • Windows Server 2022

  • Windows Server 2022 (Server Core installation)

  • Windows Server 2025 (Server Core installation)

  • Windows Server 2025

Remediation

Install KB5122876. Install KB5122882. Install KB5122871.

Vendor-listed fixes

  • 10.0.17763.9245

  • 10.0.20348.5622

  • 10.0.26100.33438

CVEs in this advisory 1

Updates

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Added to SecurityAlert

    We collected the advisory from the official source.

  3. Confirmed at the source

    Our collector saw this advisory during a later source check.