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CVE-2026-105016

Critical CVSS 9.8

Published 2026-10-13 ยท last changed 2026-10-13

The fix

Microsoft fixes this in updatesKB5130034, KB5130035, KB5126653, KB5127648, KB5127646, KB5126655, KB5126646. The fixed build differs per Windows version, so the row that matters is the one matching the machine you are looking at.

Windows version Fixed in build Update Released
.NET 10.0 installed on Windows 10.0.14 configuration change 2026-10-13
.NET 11.0 installed on Windows 11.0.0-rc.2.26504.105 configuration change 2026-10-13
.NET 8.0 installed on Windows 8.0.32 KB5130034 2026-10-13
.NET 9.0 installed on Windows 9.0.21 KB5130035 2026-10-13
Windows 11 Version 23H2 for ARM64-based Systems 10.0.22631.7652 KB5126653 2026-10-13
Windows 11 Version 23H2 for x64-based Systems 10.0.22631.7652 KB5126653 2026-10-13
Windows 11 Version 24H2 for ARM64-based Systems 10.0.26100.9711 KB5127648 2026-10-13
Windows 11 Version 24H2 for x64-based Systems 10.0.26100.9711 KB5127648 2026-10-13
Windows 11 Version 25H2 for ARM64-based Systems 10.0.26200.9711 KB5127648 2026-10-13
Windows 11 Version 25H2 for x64-based Systems 10.0.26200.9711 KB5127648 2026-10-13
Windows 11 Version 26H1 for ARM64-based Systems 10.0.28000.3231 KB5127646 2026-10-13
Windows 11 version 26H1 for x64-based Systems 10.0.28000.3231 KB5127646 2026-10-13
Windows 11 Version 26H2 for ARM64-based Systems 10.0.26300.9711 KB5127648 2026-10-13
Windows 11 Version 26H2 for x64-based Systems 10.0.26300.9711 KB5127648 2026-10-13
Windows Server 2022 10.0.20348.5761 KB5126655 2026-10-13
Windows Server 2022 (Server Core installation) 10.0.20348.5761 KB5126655 2026-10-13
Windows Server 2025 10.0.26100.33650 KB5126646 2026-10-13
Windows Server 2025 (Server Core installation) 10.0.26100.33650 KB5126646 2026-10-13

Having the KB is not the same as knowing whether a machine has it. Windows updates supersede each other, so the update you installed often covers a fix that shipped in an earlier one. Paste your build into the patch checker and it walks that chain for you.

What it is

Heap-based buffer overflow in Microsoft QUIC allows an unauthorized attacker to execute code over a network.

Sources

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H