add 8D release notes

Author: TaraOverfield

docs/framework/release-notes/2025/08-26-august-cumulative-update-preview.md

@@ -0,0 +1,47 @@
+---
+title: April 2025 cumulative update preview
+description: Learn about the improvements in the .NET Framework April 2025 cumulative update preview.
+ms.date: 08/26/2025
+---
+# August 2025 cumulative update preview
+
+_Released August 26, 2025_
+
+## Summary of what's new in this release
+
+- [Security improvements](#security-improvements)
+- [Quality and reliability improvements](#quality-and-reliability-improvements)
+
+### Security improvements
+
+There are no new security improvements in this release. This update is cumulative and contains all previously released security improvements.
+
+### Quality and reliability improvements
+
+#### ASP.NET
+
+Addresses an issue in ASP.NET where some error events fail to log properly in the Windows Event log. (*Applies to: .NET Framework 4.8, 4.8.1*)
+
+#### WPF
+
+Addressed an update for GB18030 certificate for Chinese language changes. (*Applies to: .NET Framework 4.8, 4.8.1*)
+
+## 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 preview |
+| --- | --- |
+| **Windows 11, version 24H2** | |
+| .NET Framework 3.5, 4.8.1 | [5064401](https://support.microsoft.com/kb/5064401) |
+| **Windows 11, version 22H2 and Windows 11, version 23H2** | |
+| .NET Framework 3.5, 4.8.1 | [5064403](https://support.microsoft.com/kb/5064403) |
+| **Windows 10, version 22H2** | **[5064794](https://support.microsoft.com/kb/5064794)** |
+| .NET Framework 3.5, 4.8 | [5064399](https://support.microsoft.com/kb/5064399) |
+| .NET Framework 3.5, 4.8.1 | [5064400](https://support.microsoft.com/kb/5064400) |
+
+The operating system row lists a KB that's used for update offering purposes. When the operating system KB is offered, the applicability logic determines the specific .NET Framework update(s) installed. Updates for individual .NET Framework versions are installed based on the version of .NET Framework that is already present on the device. Because of this, the operating system KB is not expected to be listed as installed updates on the device. The expected updates installed are the .NET Framework-specific version updates listed in the previous table.

docs/framework/release-notes/release-notes.md

@@ -11,7 +11,9 @@ 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 22, 2025 - [cumulative update preview](./2025/04-22-april-cumulative-update-preview.md) **New Release**
+* August 26, 2025 - [cumulative update preview](./2025/08-26-august-cumulative-update-preview.md) **New Release**
+* July 8, 2025 - [cumulative update](./2025/07-08-july-cumulative-update.md)
+* April 22, 2025 - [cumulative update preview](./2025/04-22-april-cumulative-update-preview.md)
 * April 8, 2025 - [cumulative update](./2025/04-08-april-cumulative-update.md)
 * March 25, 2025 - [cumulative update preview](./2025/03-25-march-cumulative-update-preview.md)
 * January 28, 2025 - [cumulative update preview](./2025/01-28-january-cumulative-update-preview.md)

docs/framework/toc.yml

@@ -699,6 +699,8 @@ items:
       href: release-notes/2025/04-22-april-cumulative-update-preview.md
     - name: July 2025 cumulative update
       href: release-notes/2025/07-08-july-cumulative-update.md
+    - name: August 2025 cumulative update
+      href: release-notes/2025/08-12-august-cumulative-update-preview.md
   - name: What's new
     href: whats-new/index.md
   - name: What's new in accessibility