The Update BureauKB5039886: Cumulative update for .NET Framework, versions 3.5 and 4.8, on Windows 10 1809 and Windows Server 2019, July 2024. Temporary-folder paths change; WinForms memory leaks addressed
In short
The update addresses CVE-2024-38081, which the page describes as a remote code execution vulnerability, and changes how .NET gets temporary-folder paths on some Windows versions.
Does it affect you? Applies to: Devices running Windows 10, version 1809, or Windows Server 2019 with .NET Framework 3.5 or 4.8 installed.
Review notes Additional details from the official release notes (1) Read note
-
Known issues
On Windows versions exposing
GetTempPath2, .NET uses that API; a SYSTEM process gets%WINDIR%\SystemTemp, which is inaccessible to non-SYSTEM processes. Microsoft says this behavior is by design and affected applications are expected to adapt their code.
The official sources are linked at the end of the page.
What changes
Fixes 2 changes
.NET Framework
-
The update addresses CVE-2024-38081, a security vulnerability in .NET Framework.1
The page describes the vulnerability as elevation of privilege and says the security update addresses a remote code execution vulnerability.
Winforms
-
The size of memory leaks involving WinForms accessibility objects held in memory is addressed.2
The issue involves ref-counting of
AccessibleObjectsheld in memory.
Improvement 1 change
System.IO.Path.GetTempPath
For: Application developers
-
Some applications may get a different temporary-folder path after the security fix. Affected software is expected to adapt to the new behavior.3
On Windows versions that expose the
GetTempPath2Win32 API,System.IO.Path.GetTempPathinvokes it. In that case, a SYSTEM process returns%WINDIR%\SystemTemp, which is inaccessible to non-SYSTEM processes.
Technical details
Data sheet · Security · Downloads · Components Click to collapse or expand
Data sheet
- Released
- 2024-07-09
- Classification
- Security Updates
- Type
- Cumulative update
- Restart
- Required
- Replaces
- KB5037933, KB5036610
- Replaced by
- KB5044022
| Version | File version | Channel |
|---|---|---|
| 3.5 | 2.0.50727.9064 | General availability |
| 4.8 | 4.8.4739.0 | General availability |
Security
| Vulnerability | Severity | CVSS |
|---|---|---|
|
.NET, .NET Framework, and Visual Studio Elevation of Privilege Vulnerability
|
Not rated | — |
Downloads (Microsoft Update Catalog)
x64
Windows 10 Enterprise LTSC 2019 / Windows Server 2019
88.3 MB
x86
Windows 10 Enterprise LTSC 2019
49.7 MB
Updated components
59 files changed since the previous update for the same versions.
| Top changed components | Files |
|---|---|
| WPF | 16 |
| .NET runtime (CLR) | 14 |
| ASP.NET | 6 |
| Windows Forms | 2 |
Sources
Updated
Cited passages from Microsoft's official notes (3)
-
1.
CVE-2024-38081 - .NET Framework Elevation of Privilege Vulnerability This security update addresses a remote code execution vulnerability detailed in CVE-2024-38081.
support.microsoft.com -
2.
Addresses an issue with the size of memory leaks associated with AccessibleObjects held in memory due to ref-counting.
support.microsoft.com -
3.
When calling this function from a process running as SYSTEM it will return the path %WINDIR%\SystemTemp, which is inaccessible to non-SYSTEM processes.
support.microsoft.com
Checked automatically: 7 of 8 checks passed, 3 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 5/5, clarity 4/5, completeness 4/5. 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