October 13, 2026

The October 13, 2026 update for Windows 11, version 26H1 includes security and cumulative reliability improvements in .NET Framework 3.5. We recommend that you apply this update as part of your regular maintenance routines. Before you install this update, see the Prerequisites and Restart requirement sections.

Security Improvements

CVE-2026-58280 - .NET Framework Denial of Service vulnerability This security update addresses a denial of service vulnerability detailed in CVE-2026-58280.

CVE-2026-62886 - .NET Framework Elevation of Privilege vulnerability This security update addresses an elevation of privilege vulnerability detailed in CVE-2026-62886.

CVE-2026-69651 - .NET Framework Denial of Service vulnerability This security update addresses a denial of service vulnerability detailed in CVE-2026-69651.

CVE-2026-70007 - .NET Framework Remote Code Execution vulnerability This security update addresses a remote code execution vulnerability detailed in CVE-2026-70007.

CVE-2026-70035 - .NET Framework Remote Code Execution vulnerability This security update addresses a remote code execution vulnerability detailed in CVE-2026-70035.

CVE-2026-70174 - .NET Framework Remote Code Execution vulnerability This security update addresses a remote code execution vulnerability detailed in CVE-2026-70174.

CVE-2026-83520 - .NET Framework Remote Code Execution vulnerability This security update addresses a remote code execution vulnerability detailed in CVE-2026-83520.

CVE-2026-84008 - .NET Framework Denial of Service vulnerability This security update addresses a denial of service vulnerability detailed in CVE-2026-84008.

CVE-2026-85363 - .NET Framework Elevation of Privilege vulnerability This security update addresses an elevation of privilege vulnerability detailed in CVE-2026-85363.

CVE-2026-87697 - .NET Framework Remote Code Execution vulnerability This security update addresses a remote code execution vulnerability detailed in CVE-2026-87697.

CVE-2026-96222 - .NET Framework Spoofing vulnerability This security update addresses a spoofing vulnerability detailed in CVE-2026-96222.

CVE-2026-96224 - .NET Framework Remote Code Execution vulnerability This security update addresses a remote code execution vulnerability detailed in CVE-2026-96224.

CVE-2026-96233 - .NET Framework Denial of Service vulnerability This security update addresses a denial of service vulnerability detailed in CVE-2026-96233.

CVE-2026-96958 - .NET Framework Denial of Service vulnerability This security update addresses a denial of service vulnerability detailed in CVE-2026-96958.

CVE-2026-96959 - .NET Framework Denial of Service vulnerability This security update addresses a denial of service vulnerability detailed in CVE-2026-96959.

CVE-2026-96960 - .NET Framework Denial of Service vulnerability This security update addresses a denial of service vulnerability detailed in CVE-2026-96960.

CVE-2026-97801 - .NET Framework Tampering vulnerability This security update addresses a tampering vulnerability detailed in CVE-2026-97801.

Quality and Reliability Improvements

There are no new Quality and Reliability Improvements in this update.

Known issues in this update

Microsoft is not currently aware of any issues in this update.

How to get this update

For a list of the files that are provided in this update, download the file information for cumulative update .

To apply this update, you must have .NET Framework 3.5 installed.

You must restart the computer after you apply this update if any affected files are being used. We recommend that you exit all .NET Framework-based applications before you apply this update.

How to obtain help and support for this update

Help for installing updates: Windows Update FAQ

Protect yourself online and at : Windows Security support

Local support according to your country/region: International Support