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5B .NET Framework release notes #53678

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5B .NET Framework release notes
TaraOverfield May 11, 2026
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Fix missing newline at end of release notes file
TaraOverfield May 12, 2026
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86 changes: 86 additions & 0 deletions docs/framework/release-notes/2026/05-12-may-cumulative-update.md
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---
title: May 2026 cumulative update
description: Learn about the improvements in the .NET Framework May 2026 cumulative update.
ms.date: 05/12/2026
---
# May 2026 cumulative update

_Released May 12, 2026_

## Summary of what's new in this release

- [Security improvements](#security-improvements)
- [Quality and reliability improvements](#quality-and-reliability-improvements)

### Security improvements

#### CVE-2026-32177 – Elevation of Privilege vulnerability

This security update addresses an elevation of privilege vulnerability detailed in [CVE-2026-32177](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-32177).

#### CVE-2026-35433 – Elevation of Privilege vulnerability

This security update addresses an elevation of privilege vulnerability detailed in [CVE-2026-35433](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-35433).

### Quality and reliability improvements

There are no additional quality and reliability improvements in this release. This update is cumulative and contains all previously released quality and reliability improvements.

## Known issues in this release

This release contains no known issues.

## Summary tables

The following table outlines the updates in this release.

| Product version | Cumulative update |
| --- | --- |
| **Windows 11, version 26H1** | |
| .NET Framework 4.8.1 | [5087055](https://support.microsoft.com/kb/5087055) |
| **Windows 11, version 25H2** | |
| .NET Framework 3.5, 4.8.1 | [5087051](https://support.microsoft.com/kb/5087051) |
| **Windows 11, version 24H2** | |
| .NET Framework 3.5, 4.8.1 | [5087054](https://support.microsoft.com/kb/5087054) |
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| **Microsoft server operating system, version 24H2** | |
| .NET Framework 3.5, 4.8.1 | [5087051](https://support.microsoft.com/kb/5087051) |
| **Microsoft server operating system, version 23H2** | |
| .NET Framework 3.5, 4.8.1 | [5087052](https://support.microsoft.com/kb/5087052) |
| **Windows 11, version 22H2 and Windows 11, version 23H2** | |
| .NET Framework 3.5, 4.8.1 | [5087058](https://support.microsoft.com/kb/5087058) |
| **Windows Server 2022** | **[5088862](https://support.microsoft.com/kb/5088862)** |
| .NET Framework 3.5, 4.8 | [5087068](https://support.microsoft.com/kb/5087068) |
| .NET Framework 3.5, 4.8.1 | [5087059](https://support.microsoft.com/kb/5087059) |
| **Windows 10, version 22H2** | **[5088863](https://support.microsoft.com/kb/5088863)** |
| .NET Framework 3.5, 4.8 | [5087064](https://support.microsoft.com/kb/5087064) |
| .NET Framework 3.5, 4.8.1 | [5087053](https://support.microsoft.com/kb/5087053) |
| **Windows 10, version 21H2** | **[5088859](https://support.microsoft.com/kb/5088859)** |
| .NET Framework 3.5, 4.8 | [5087064](https://support.microsoft.com/kb/5087064) |
| .NET Framework 3.5, 4.8.1 | [5087053](https://support.microsoft.com/kb/5087053) |
| **Windows 10 1809 and Windows Server 2019** | **[5088864](https://support.microsoft.com/kb/5088864)** |
| .NET Framework 3.5, 4.7.2 | [5087061](https://support.microsoft.com/kb/5087061) |
| .NET Framework 3.5, 4.8 | [5087066](https://support.microsoft.com/kb/5087066) |
| **Windows 10 1607 and Windows Server 2016** | |
| .NET Framework 3.5, 4.6.2, 4.7, 4.7.1, 4.7.2 | [5087537](https://support.microsoft.com/kb/5087537) |
| .NET Framework 4.8 | [5087065](https://support.microsoft.com/kb/5087065) |

The following table is for earlier Windows and Windows Server versions for Security and Quality Rollup updates.

| Product version | Security and quality rollup |
| --- | --- |
| **Windows Server 2012 R2** | **[5088861](https://support.microsoft.com/kb/5088861)** |
| .NET Framework 3.5 | [5087049](https://support.microsoft.com/kb/5087049) |
| .NET Framework 4.6.2, 4.7, 4.7.1, 4.7.2 | [5087063](https://support.microsoft.com/kb/5087063) |
| .NET Framework 4.8 | [5087069](https://support.microsoft.com/kb/5087069) |
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| **Windows Server 2012** | **[5088860](https://support.microsoft.com/kb/5088860)** |
| .NET Framework 3.5 | [5087048](https://support.microsoft.com/kb/5087048) |
| .NET Framework 4.6.2, 4.7, 4.7.1, 4.7.2 | [5087062](https://support.microsoft.com/kb/5087062) |
| .NET Framework 4.8 | [5087067](https://support.microsoft.com/kb/5087067) |

The operating system rows list a KB that's used for update-offering purposes. When the operating system KB is offered, the applicability logic determines the specific .NET Framework updates that will be installed. Updates for individual .NET Framework versions are installed based on the version of .NET Framework that's already present on the device. Because of this, the operating system KB is not expected to be listed as an installed update on the device. The expected updates to be installed are the .NET Framework specific version updates listed in the preceding table.

This 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.

| Product version | .NET Framework 3.5 product update |
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| --- | --- |
| **Windows 11, version 26H1** | [5087077](https://support.microsoft.com/kb/5087077) |
3 changes: 2 additions & 1 deletion docs/framework/release-notes/release-notes.md
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Expand Up @@ -11,7 +11,8 @@ The .NET Framework updates include cumulative security and reliability improveme

.NET Framework cumulative update releases are discussed in detail in the following individual release notes:

* April 14, 2026 - [cumulative update](./2026/04-14-april-cumulative-update.md) **New Release**
* May 12, 2026 - [cumulative update](./2026/05-12-may-cumulative-update.md) **New Release**
* April 14, 2026 - [cumulative update](./2026/04-14-april-cumulative-update.md)
* February 10, 2026 - [cumulative update](./2026/02-10-february-cumulative-update.md)
* January 29, 2026 - [cumulative update preview](./2026/01-29-january-cumulative-update-preview.md)
* October 28, 2025 - [cumulative update preview](./2025/10-28-october-cumulative-update-preview.md)
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items:
- name: Overview and index
href: release-notes/release-notes.md
- name: May 2026 cumulative update
href: release-notes/2026/05-12-may-cumulative-update.md
- name: April 2026 cumulative update
href: release-notes/2026/04-14-april-cumulative-update.md
- name: February 2026 cumulative update
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