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.NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 Security update
Patch Tuesday

KB5039884

KB5039884: Cumulative update for .NET Framework, versions 3.5 and 4.8, on Windows 10 21H2/22H2, July 2024. Addresses elevation flaw; temp paths change where GetTempPath2 exists

In short

The update addresses CVE-2024-38081 and a WinForms memory-leak issue. On Windows versions that expose the GetTempPath2 API, System.IO.Path.GetTempPath uses that API and returns its resolved path.

Does it affect you? Applies to: Devices running Windows 10 version 21H2 or 22H2 with .NET Framework 3.5 or 4.8 installed.

File version
2.0.50727.9177 · 4.8.4739.0
Security
1 fixed
Restart
Required
Review notes Additional details from the official release notes (2) Read notes
  • What changes On Windows versions that expose GetTempPath2, .NET Framework’s Path.GetTempPath behavior changes. Affected applications are expected to adapt their code.
  • Known issues The update changes Path.GetTempPath behavior on Windows versions that expose GetTempPath2; affected applications are expected to adapt. Microsoft warns that opting out disables the CVE-2024-38081 security fix and does not recommend the workaround.

The official sources are linked at the end of the page.

What changes

Fixes 2 changes

.NET Framework

  • The update addresses a security vulnerability in .NET Framework.1
    CVE-2024-38081 is an elevation-of-privilege vulnerability; the page also describes it as a remote code execution vulnerability.

Winforms

  • Memory leaks linked to WinForms accessibility objects are addressed.2
    Addresses memory leaks associated with AccessibleObjects held in memory due to reference counting.

Improvement 1 change

System.IO.Path.GetTempPath

  • On Windows versions that expose GetTempPath2, apps using System.IO.Path.GetTempPath receive the path resolved by that API. For SYSTEM processes, this is %WINDIR%\SystemTemp, which non-SYSTEM processes cannot access.3
    When GetTempPath2 is exposed, System.IO.Path.GetTempPath invokes it. The changed behavior is by design; affected applications are expected to adapt.

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
KB5037592, KB5036608
Replaced by
KB5044020
VersionFile versionChannel
3.5 2.0.50727.9177 General availability
4.8 4.8.4739.0 General availability

Security

1 vulnerability fixed
1 not rated
VulnerabilitySeverityCVSS
CVE-2024-38081
.NET, .NET Framework, and Visual Studio Elevation of Privilege Vulnerability
 Not rated —

Downloads (Microsoft Update Catalog)

x64 Windows 10 Enterprise LTSC 2021 / Windows 10, version 22H2
75.9 MB
windows10.0-kb5039884-x64-ndp48.msu Main update · KB5039884 SHA-1: 24e7f9b4…9157e1
Arm64 Windows 10 Enterprise LTSC 2021 / Windows 10, version 22H2
47.5 MB
windows10.0-kb5039884-arm64-ndp48.msu Main update · KB5039884 SHA-1: 4409e9ce…48fee2
x86 Windows 10 Enterprise LTSC 2021 / Windows 10, version 22H2
47.5 MB
windows10.0-kb5039884-x86-ndp48.msu Main update · KB5039884 SHA-1: 99b64258…a00f25

Updated components

157 files changed since the previous update for the same versions.

Top changed componentsFiles
WPF42
.NET runtime (CLR)21
WCF18
ASP.NET9
Windows Forms3

Sources

Updated
Cited passages from Microsoft's official notes (3)
  1. 1. This security update addresses a remote code execution vulnerability detailed in CVE-2024-38081. support.microsoft.com
  2. 2. Addresses an issue with the size of memory leaks associated with AccessibleObjects held in memory due to ref-counting. support.microsoft.com
  3. 3. If windows version exposes the GetTempPath2 Win32 API, this method invokes that API and returns the resolved path. 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 4/5, clarity 4/5, completeness 3/5. 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