April 14, 2026-KB5084165 Cumulative Update for .NET Framework 3.5 for Windows 11, version 26H1 (build 28000) and later
Applies To
Revised May 13, 2026:
Updated 'How to get this update' section.
Release Date:April 14, 2026
Version:.NET Framework 3.5
The April 14, 2026 update installs the complete .NET Framework 3.5 product for Windows 11, version 26H1 (build version 28000) and newer. Unlike traditional cumulative updates that patch individual components, this delivers the full .NET Framework 3.5 product as a standalone installer. It replaces any previously installed version. Before you install this update, see the Prerequisites and Restart requirement sections.
Summary
Security Improvements
CVE-2026-32178 - .NET Framework Remote Code Execution vulnerability This security update addresses a remote code execution vulnerability detailed in CVE-2026-32178.
CVE-2026-32203 - .NET Framework Denial of Service vulnerability This security update addresses a denial-of-service vulnerability detailed in CVE-2026-32203.
CVE-2026-32226 - .NET Framework Denial of Service vulnerability This security update addresses a denial-of-service vulnerability detailed in CVE-2026-32226.
CVE-2026-23666 - .NET Framework Denial of Service vulnerability This security update addresses a denial-of-service vulnerability detailed in CVE-2026-23666.
CVE-2026-26171 - .NET Framework Security Feature Bypass vulnerability This security update addresses a security feature bypass vulnerability detailed in CVE-2026-26171.
CVE-2026-33116 - .NET Framework Information Disclosure vulnerability This security update addresses an information disclosure vulnerability detailed in CVE-2026-33116.
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
Install this update
|
Release Channel |
Available |
Next Step |
|
Microsoft Update |
No |
See note |
|
Microsoft Update Catalog |
No |
See note |
|
Windows Server Update Services (WSUS) |
No |
See note |
Note: This update is no longer available. At this time, no functional issues have been reported with this update. To ensure your device continues to receive the latest security updates and quality improvements, we recommend installing the most recent update. Refer to the side navigation history for links to latest versions.
File information
For a list of the files that are provided in this update, download the file information for cumulative update.
Prerequisites
To apply this update, you must have .NET Framework 3.5 installed.
Restart requirement
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.
Information about uninstallation
Uninstalling this update removes .NET Framework 3.5 entirely. It does not revert to a previously installed version.Â
How to obtain help and support for this update
-
Help for installing updates: Windows Update FAQ
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Protect yourself online and at home: Windows Security support
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Local support according to your country: International Support
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