The Update BureauKB5064401: Cumulative update for .NET Framework, versions 3.5 and 4.8.1, on Windows 11 24H2 and Windows Server 2025, September 2025. ASP.NET event logging fixed; WPF certificate update addressed
Addresses missing ASP.NET error events in the Windows Event log and a WPF GB18030 certificate update. You must restart after installation if affected files are in use.
Does it affect you? Applies to: Devices running Windows 11, version 24H2, or Microsoft server operating system version 24H2 (Windows Server 2025), with .NET Framework 3.5 or 4.8.1 installed.
Review notes Additional details from the official release notes (2) Read notes
- What changes The update addresses an ASP.NET issue that caused some error events not to be logged properly in the Windows Event log.
- What changes The update addresses a WPF change for the GB18030 certificate related to Chinese language changes. Microsoft does not specify a narrower affected-device audience.
The official sources are linked at the end of the page.
What changes
Fixes 2 changes
ASP.NET
For: Devices running ASP.NET applications
-
Some ASP.NET error events are logged properly in the Windows Event log.1
Addresses an issue where some error events fail to log properly in the Windows Event log.
WPF
For: Devices using WPF with Chinese language changes
-
The WPF update for the GB18030 certificate related to Chinese language changes is addressed.2
Addresses an update for the GB18030 certificate for Chinese language changes.
Technical details
Data sheet · Security · Downloads · Components Click to collapse or expand
Data sheet
- Released
- 2025-09-09
- Classification
- Updates
- Type
- Cumulative update
- Restart
- Required
- Replaces
- KB5056579, KB5054979, KB5050577, KB5048162, KB5045934
- Replaced by
- KB5066131
| Version | File version | Channel |
|---|---|---|
| 3.5 | 2.0.50727.9179 | General availability |
| 4.8.1 | 4.8.9316.0 | General availability |
Security
No vulnerabilities are listed for this update.
Downloads (Microsoft Update Catalog)
Updated components
60 files changed since the previous update for the same versions.
| Top changed components | Files |
|---|---|
| WPF | 22 |
| ASP.NET | 10 |
Verified in package: changed files confirm ASP.NET, WPF.
Sources
Cited passages from Microsoft's official notes (2)
-
1.
Addressed an issue in ASP.NET where some error events fail to log properly in the Windows Event log.
support.microsoft.com -
2.
-Addressed an update for GB18030 certificate for Chinese language changes.
support.microsoft.com
Checked automatically: 8 of 8 checks passed, 2 quoted passages · compared with Microsoft's page on Oct 20, 2026
- Quotes found in the official pages: passed
- Numbers found in the sources: passed
- Vulnerabilities from the dossier only: passed
- Links to allowed domains only: passed
- Every official change covered: passed
- Readable plain text: passed
- Changes confirmed by the file list: passed
- Sources agree: passed
A second AI read the text against the sources: correctness 3/5, clarity 3/5, completeness 5/5. How we work
Published by The Update Bureau. Written with AI from Microsoft's own documents, checked by rules and a second AI. How we work · Report a mistake