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CVE-2026-47304

High CVSS 8.1

Published 2026-07-14 ยท last changed 2026-07-24

The fix

Microsoft fixes this in updatesKB5099535, KB5100989, KB5101000, KB5101004, KB5101001, KB5100998, KB5101014, KB5101005, KB5101003, KB5101008, KB5101006, KB5101010, KB5100984, KB5100985, KB5100990, KB5100991, KB5101002, KB5101007, KB5101009, KB5101011, KB5104032, KB5104033. 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
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1607 for 32-bit Systems 2.0.50727.8983 & 3.0.30729.8978 & 4.7.4143.0 KB5099535 2026-09-20
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1607 for x64-based Systems 2.0.50727.8983 & 3.0.30729.8978 & 4.7.4143.0 KB5099535 2026-09-20
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for 32-bit Systems 2.0.50727.9069 & 3.0.30729.9067 & 4.7.4143.0 KB5100989 2026-09-20
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for x64-based Systems 2.0.50727.9069 & 3.0.30729.9067 & 4.7.4143.0 KB5100989 2026-09-20
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows Server 2016 2.0.50727.8983 & 3.0.30729.8978 & 4.7.4143.0 KB5099535 2026-09-20
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows Server 2016 (Server Core installation) 2.0.50727.8983 & 3.0.30729.8978 & 4.7.4143.0 KB5099535 2026-09-20
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows Server 2019 2.0.50727.9069 & 3.0.30729.9067 & 4.7.4143.0 KB5100989 2026-09-20
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows Server 2019 (Server Core installation) 2.0.50727.9069 & 3.0.30729.9067 & 4.7.4143.0 KB5100989 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 21H2 for 32-bit Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101000 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 21H2 for ARM64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101000 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 21H2 for x64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101000 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 22H2 for 32-bit Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101000 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 22H2 for ARM64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101000 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 22H2 for x64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101000 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 23H2 for ARM64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101004 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 23H2 for x64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101004 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 24H2 for ARM64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101001 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 24H2 for x64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101001 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 25H2 for ARM64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9340.0 KB5100998 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 25H2 for x64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9340.0 KB5100998 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 26H1 for ARM64-based Systems 2.0.50727.9182 & 3.0.30729.9168 KB5101014 2026-07-21
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 26H1 for x64-based Systems 2.0.50727.9182 & 3.0.30729.9168 KB5101014 2026-07-21
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2022 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101005 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2022 (Server Core installation) 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0 KB5101005 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2025 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9340.0 KB5101003 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2025 (Server Core installation) 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9340.0 KB5101003 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for 32-bit Systems 2.0.50727.9069 & 3.0.30729.9067 & 4.8.4803.0 KB5101008 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for x64-based Systems 2.0.50727.9069 & 3.0.30729.9067 & 4.8.4803.0 KB5101008 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 21H2 for 32-bit Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.4803.0 KB5101006 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 21H2 for ARM64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.4803.0 KB5101006 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 21H2 for x64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.4803.0 KB5101006 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 22H2 for 32-bit Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.4803.0 KB5101006 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 22H2 for ARM64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.4803.0 KB5101006 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 22H2 for x64-based Systems 2.0.50727.9182 & 3.0.30729.9168 & 4.8.4803.0 KB5101006 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2019 2.0.50727.9069 & 3.0.30729.9067 & 4.8.4803.0 KB5101008 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2019 (Server Core installation) 2.0.50727.9069 & 3.0.30729.9067 & 4.8.4803.0 KB5101008 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2022 2.0.50727.9182 & 3.0.30729.9168 & 4.8.4803.0 KB5101010 2026-09-20
Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2022 (Server Core installation) 2.0.50727.9182 & 3.0.30729.9168 & 4.8.4803.0 KB5101010 2026-09-20
Microsoft .NET Framework 3.5 on Windows 11 Version 26H1 for ARM64-based Systems 2.0.50727.9182 & 3.0.30729.9168 KB5101014 2026-09-20
Microsoft .NET Framework 3.5 on Windows 11 version 26H1 for x64-based Systems 2.0.50727.9182 & 3.0.30729.9168 KB5101014 2026-09-20
Microsoft .NET Framework 3.5 on Windows Server 2012 2.0.50727.8983 & 3.0.30729.8978 KB5100984 2026-09-20
Microsoft .NET Framework 3.5 on Windows Server 2012 R2 2.0.50727.8983 & 3.0.30729.8978 KB5100985 2026-09-20
Microsoft .NET Framework 3.5 on Windows Server 2012 R2 (Server Core installation) 2.0.50727.8983 & 3.0.30729.8978 KB5100985 2026-09-20
Microsoft .NET Framework 3.5 on Windows Server 2012 (Server Core installation) 2.0.50727.8983 & 3.0.30729.8978 KB5100984 2026-09-20
Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 4.7.4143.0 KB5100990 2026-09-20
Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 R2 4.7.4143.0 KB5100991 2026-09-20
Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 R2 (Server Core installation) 4.7.4143.0 KB5100991 2026-09-20
Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 (Server Core installation) 4.7.4143.0 KB5100990 2026-09-20
Microsoft .NET Framework 4.8.1 on Windows 11 Version 26H1 for ARM64-based Systems 4.8.9340.0 KB5101002 2026-09-20
Microsoft .NET Framework 4.8.1 on Windows 11 version 26H1 for x64-based Systems 4.8.9340.0 KB5101002 2026-09-20
Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for 32-bit Systems 4.8.4803.0 KB5101007 2026-09-20
Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for x64-based Systems 4.8.4803.0 KB5101007 2026-09-20
Microsoft .NET Framework 4.8 on Windows Server 2012 4.8.4803.0 KB5101009 2026-09-20
Microsoft .NET Framework 4.8 on Windows Server 2012 R2 4.8.4803.0 KB5101011 2026-09-20
Microsoft .NET Framework 4.8 on Windows Server 2012 R2 (Server Core installation) 4.8.4803.0 KB5101011 2026-09-20
Microsoft .NET Framework 4.8 on Windows Server 2012 (Server Core installation) 4.8.4803.0 KB5101009 2026-09-20
Microsoft .NET Framework 4.8 on Windows Server 2016 4.8.4803.0 KB5101007 2026-09-20
Microsoft .NET Framework 4.8 on Windows Server 2016 (Server Core installation) 4.8.4803.0 KB5101007 2026-09-20
.NET 8.0 installed on Windows 8.0.29 KB5104032 2026-09-20
.NET 9.0 installed on Windows 9.0.18 KB5104033 2026-09-20

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

Improper verification of cryptographic signature in .NET allows an unauthorized attacker to bypass a security feature over a network.

Sources

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