The Update BureauKB5036604: Cumulative update for .NET Framework, versions 3.5 and 4.7.2, on Windows 10 1809 and Windows Server 2019, April 2024. ASP.NET slowdown fixed; security flaws addressed
In short
The update addresses a security flaw that could let an attacker run code on an affected system, updates an outdated library, and addresses an ASP.NET performance slowdown.
Does it affect you? Applies to: Devices running Windows 10, version 1809, or Windows Server 2019 with .NET Framework 3.5 or 4.7.2 installed.
Review notes Additional details from the official release notes (2) Read notes
- In short The update addresses an issue where the version of the OSS zlib library is out of date.
- What changes The update addresses an issue where the version of the OSS zlib library is out of date.
The official sources are linked at the end of the page.
What changes
Fixes 4 changes
.NET Framework
3 items
-
Addresses a security flaw that could let an attacker run code on an affected system.1
Addresses CVE-2024-21409, a .NET Framework remote code execution vulnerability.
-
Updates an outdated library version as part of a security improvement.2
Addresses an issue where the version of the OSS zlib library is out of date.
-
Addresses a security issue in a data-fetching process.3
Addresses an issue in the AIA fetching process.
ASP.NET
Verified in package
-
Addresses a performance slowdown after the January Security and Quality update.4
Addresses an issue with
JavaScriptSerializer.
Technical details
Data sheet · Security · Downloads · Components Click to collapse or expand
Data sheet
- Released
- 2024-04-09
- Classification
- Security Updates
- Type
- Cumulative update
- Restart
- Required
- Replaces
- KB5034619, KB5033904
- Replaced by
- KB5039879
| Version | File version | Channel |
|---|---|---|
| 3.5 | 2.0.50727.9063 | General availability |
| 4.7.2 | 4.7.4092.0 | General availability |
Security
| Vulnerability | Severity | CVSS |
|---|---|---|
|
.NET, .NET Framework, and Visual Studio Remote Code Execution Vulnerability
|
Not rated | — |
Downloads (Microsoft Update Catalog)
x64
Windows 10 Enterprise LTSC 2019 / Windows Server 2019
78.5 MB
Arm64
Windows 10 Enterprise LTSC 2019
44.4 MB
x86
Windows 10 Enterprise LTSC 2019
44.4 MB
Updated components
123 files changed since the previous update for the same versions.
| Top changed components | Files |
|---|---|
| WPF | 45 |
| WCF | 18 |
| ASP.NET | 15 |
Verified in package: changed files confirm ASP.NET.
Sources
Updated
Cited passages from Microsoft's official notes (4)
-
1.
This security update addresses a remote code execution vulnerability detailed in CVE-2024-21409.
support.microsoft.com -
2.
This security update addresses an issue where version of the OSS zlib library is out of date.
support.microsoft.com -
3.
This security update addresses an issue in AIA fetching process.
support.microsoft.com -
4.
Addresses an issue with JavaScriptSerializer where after installing the January Security and Quality update there is a performance degradation.
support.microsoft.com
Checked automatically: 7 of 8 checks passed, 4 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: not passed
A second AI read the text against the sources: correctness 4/5, clarity 5/5, 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