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Microsoft Security Response CenterCVE-2026-97801

.NET Framework Tampering Vulnerability

HighVendor CVSS 7.5 / 10 1 CVE Published Oct 13, 2026 at 7:00 AM UTC
Get alerts for Microsoft .NET Framework 3.5 AND 4.8.1 on Windows

Summary

Improper validation of specified type of input in .NET Framework allows an unauthorized attacker to perform tampering over a network.

Products covered

  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 version 21H2

  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 version 22H2

  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 24H2

  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 25H2

  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2025

  • Microsoft .NET Framework 4.8.1 on Windows 11 version 26H1

  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 23H2

  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2022

Show 19 more products

  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 26H2

  • Microsoft .NET Framework 3.5 on Windows 11 version 26H1

  • Microsoft .NET Framework 3.5 on Windows Server 2012

  • Microsoft .NET Framework 3.5 on Windows Server 2012 R2

  • Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 version 1607

  • Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016

  • Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2019

  • Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 version 1809

  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 version 1809

  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 version 21H2

  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 version 22H2

  • Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2019

  • Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2022

  • Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012

  • Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 R2

  • Microsoft .NET Framework 4.8 on Windows 10 version 1607

  • Microsoft .NET Framework 4.8 on Windows Server 2012

  • Microsoft .NET Framework 4.8 on Windows Server 2012 R2

  • Microsoft .NET Framework 4.8 on Windows Server 2016

Remediation

Install KB5127689. Install KB5127690. Install KB5127691. Install KB5127692. Install KB5127693. Install KB5127694. Install KB5127696. Install KB5127660. Install KB5127664. Install KB5126868. Install KB5127666. Install KB5127685. Install KB5127683. Install KB5127687. Install KB5127667. Install KB5127668. Install KB5127684. Install KB5127686. Install KB5127688.

Vendor-listed fixes

  • 2.0.50727.9188 AND 3.0.30729.9171 AND 4.8.9363.0

  • 4.8.9363.0

  • 2.0.50727.9188 AND 3.0.30729.9171 AND 4.8.10008.0

  • 2.0.50727.9188 AND 3.0.30729.9171

  • 2.0.50727.8987 AND 3.0.30729.8982

  • 2.0.50727.8987 AND 3.0.30729.8982 AND 4.7.4150.0

  • 2.0.50727.9073 AND 3.0.30729.9070 AND 4.7.4150.0

  • 2.0.50727.9073 AND 3.0.30729.9070 AND 4.8.4811.0

Show 3 more fixes

  • 2.0.50727.9188 AND 3.0.30729.9171 AND 4.8.4811.0

  • 4.7.4150.0

  • 4.8.4811.0

CVEs in this advisory 1

CVE-2026-97801

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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