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Microsoft Security Response CenterCVE-2026-69789

Windows Reliable Multicast Transport Driver (RMCAST) Remote Code Execution Vulnerability

CriticalVendor CVSS 7.5 / 10 1 CVE Published Oct 13, 2026 at 7:00 AM UTC
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Summary

Heap-based buffer overflow in Reliable Multicast Transport Driver (RMCAST) allows an unauthorized attacker to execute code over an adjacent 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 10 Version 21H2 for 32-bit Systems

  • Windows 10 Version 21H2 for ARM64-based Systems

Show 22 more products

  • Windows 10 Version 21H2 for x64-based Systems

  • Windows 10 Version 22H2 for x64-based Systems

  • Windows 10 Version 22H2 for ARM64-based Systems

  • Windows 10 Version 22H2 for 32-bit Systems

  • Windows Server 2025 (Server Core installation)

  • Windows 11 Version 25H2 for ARM64-based Systems

  • Windows 11 Version 25H2 for x64-based Systems

  • Windows 11 Version 23H2 for ARM64-based Systems

  • Windows 11 Version 23H2 for x64-based Systems

  • Windows 11 Version 24H2 for ARM64-based Systems

  • Windows 11 Version 24H2 for x64-based Systems

  • Windows Server 2025

  • Windows 11 version 26H1 for x64-based Systems

  • Windows 11 Version 26H1 for ARM64-based Systems

  • Windows 10 Version 1607 for 32-bit Systems

  • Windows 10 Version 1607 for x64-based Systems

  • Windows Server 2016

  • Windows Server 2016 (Server Core installation)

  • Windows Server 2012

  • Windows Server 2012 (Server Core installation)

  • Windows Server 2012 R2

  • Windows Server 2012 R2 (Server Core installation)

Remediation

Install KB5122876. Install KB5122882. Install KB5122878. Install KB5122871. Install KB5124008. Install KB5122880. Install KB5124012. Install KB5123099. Install KB5123065. Install KB5123066.

Vendor-listed fixes

  • 10.0.17763.9245

  • 10.0.20348.5622

  • 10.0.19044.7725

  • 10.0.19045.7725

  • 10.0.26100.33438

  • 10.0.26200.9445

  • 10.0.22631.7582

  • 10.0.26100.9445

Show 4 more fixes

  • 10.0.28000.2954

  • 10.0.14393.9512

  • 6.2.9200.26349

  • 6.3.9600.23398

CVEs in this advisory 1

CVE-2026-69789

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.

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