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.NET Framework

.NET Framework updates

All published releases for .NET Framework, newest first: what each update changes, whether to install it and any confirmed known issues. Latest release: October 13, 2026.

1 active known issue →

.NET Framework updates

  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows 10 21H2, 22H2 Update

    KB5042056

    Visual Studio build conflicts and WebForms metadata issues addressed

    Addresses .NET reliability issues involving zlib, UI automation, serialization, ASP.NET WebForms, and Visual Studio compilation. It adds no new security improvements.

    Check the newer update, KB5044020

    Key changes 5 changes

    • Fix .NET Libraries: The update addresses an issue with updating the zlib file to its latest version.
    • Fix .NET Fundamentals: The update addresses an issue affecting the rendering of UI automation ListView sub-items.
    • Fix .NET Fundamentals: The update addresses an issue where BinaryFormatter mutations could bypass the serialization binder.

    Read update Source: Microsoft

    Builds
    4.8.4744.0 · 2.0.50727.9179
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows Server 2022 Update

    KB5041948

    UI automation and large ASP.NET project slowdowns addressed

    Addresses .NET reliability issues, including ListView rendering and conflicts that could slow large ASP.NET projects in Visual Studio. It adds no new security improvements.

    Check the newer update, KB5044025

    Key changes 5 changes

    • Fix .NET Libraries: The zlib file is updated to the latest version.
    • Fix .NET Fundamentals: An issue rendering ListView subitems in UI automation is addressed.
    • Fix .NET Fundamentals: An issue involving serialization binder bypasses with BinaryFormatter mutations is addressed.

    Read update Source: Microsoft

    Builds
    4.8.4749.0 · 2.0.50727.9179
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows 10 1809 · Windows Server 2019 Update

    KB5041974

    Zlib, ListView rendering and ASP.NET issues addressed

    Addresses reliability issues in zlib, UI automation, ASP.NET and Visual Studio interactions. It includes previously released security improvements but no new ones.

    Check the newer update, KB5044022

    Key changes 5 changes

    • Fix .NET Libraries: An issue with the zlib file is addressed by updating it to the latest version.
    • Fix .NET Fundamentals: An issue involving the rendering of UI automation ListView subitems is addressed.
    • Fix .NET Fundamentals: An issue involving binary formatter mutations that bypass the serialization binder is addressed.

    Read update Source: Microsoft

    Builds
    4.8.4749.0 · 2.0.50727.9066
    Restart
    Required
  • .NET Framework 4.8 .NET Framework 4.8 for Windows 10 1607 · Windows Server 2016 Update

    KB5041951

    zlib and UI automation rendering issues addressed

    The .NET Framework 4.8 update addresses reliability issues involving zlib, UI automation, binary serialization, ASP.NET WebForms, and Visual Studio. It adds no new security improvements.

    Check the newer update, KB5044021

    Key changes 5 changes

    • Fix .NET Libraries: The update addresses an issue with updating the zlib compression library.
    • Fix .NET Fundamentals: The update addresses a problem that could prevent UI automation from rendering details in ListView rows.
    • Fix .NET Fundamentals: The update addresses an issue where changes made with BinaryFormatter could bypass the serialization binder.

    Read update Source: Microsoft

    Build
    4.8.4749.0
    Restart
    Required
  • .NET Framework 3.5 / 4.7.2 .NET Framework 3.5 / 4.7.2 for Windows 10 1809 · Windows Server 2019 Update

    KB5041913

    Updates zlib and corrects .NET data handling and WebForms metadata

    The update refreshes a .NET library file and addresses two .NET issues, including unwanted metadata on some generated web pages. It contains no new security improvements.

    Check the newer update, KB5044016

    Key changes 3 changes

    • Fix .NET Libraries: A file used by .NET libraries is updated to its latest version.
    • Fix .NET Fundamentals: A .NET issue involving a bypass in handling serialized data is addressed.
    • Fix .NET Fundamentals: An affected web-page feature no longer adds certain advisory and content-rating information to pages.

    Read update Source: Microsoft

    Builds
    4.7.4108.0 · 2.0.50727.9066
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 10 22H2 Optional preview
    Preview

    KB5041168

    ListView rendering, zlib, and ASP.NET issues addressed

    Addresses several .NET Framework reliability issues, including ListView rendering, serialization, and ASP.NET project compilation problems.

    Key changes 5 changes

    • Fix .NET Libraries: The update addresses an issue with bringing the zlib file up to its latest version.
    • Fix .NET Fundamentals: The update addresses a problem that could prevent UI automation from rendering ListView subitems.
    • Fix .NET Fundamentals: The update addresses an issue where binary formatter mutations could bypass the serialization binder.

    Read update Source: Microsoft

    Builds
    4.8.9261.0 · 2.0.50727.9177
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows 10 22H2 Optional preview
    Preview

    KB5041167

    Fixes .NET list rendering and ASP.NET project slowdowns

    Addresses .NET issues involving automated list rendering, data safety checks, ASP.NET page metadata, and slowdowns in large projects using Visual Studio.

    Key changes 5 changes

    • Fix .NET Libraries: A component used to compress data is updated to the latest zlib version.
    • Fix .NET Fundamentals: Sub-items in automated interface lists can now render properly.
    • Fix .NET Fundamentals: The update addresses a case where modified data could get around a .NET safety check.

    Read update Source: Microsoft

    Builds
    4.8.4744.0 · 2.0.50727.9177
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows 10 22H2 Optional preview
    Preview

    KB5041355

    Reliability changes for framework versions 3.5, 4.8 and 4.8.1

    Includes quality and reliability improvements for .NET Framework 3.5, 4.8 and 4.8.1 on Windows 10, version 22H2. It adds no new security improvements.

    Key changes 1 change

    • Improved .NET Framework: The update includes quality and reliability improvements for .NET Framework 3.5, 4.8 and 4.8.1.

    Read update Source: Microsoft

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  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 10 21H2, 22H2 Security update

    KB5039893

    Elevation flaw fixed; temporary-path behavior changes

    CVE-2024-38081 is addressed. On Windows versions that expose `GetTempPath2`, `System.IO.Path.GetTempPath` can return a different path for SYSTEM processes, so affected software may need changes.

    Check the newer update, KB5044029

    Key changes 1 CVE · 3 changes

    • Fix .NET Framework: The update addresses an elevation-of-privilege vulnerability.
    • Fix WinForms: Addresses an issue with memory leaks associated with objects held in memory.
    • Fix .NET Fundamentals: Addresses an issue using X.509 certificates under PPL in Azure AD.

    Read update Source: Microsoft

    Builds
    4.8.9256.0 · 2.0.50727.9177
    Security
    1 vulnerability fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows Server 2022 Security update

    KB5039907

    Temporary-path behavior changes alongside a privilege fix

    The update fixes an elevation-of-privilege vulnerability in .NET Framework and changes the temporary path returned by System.IO.Path.GetTempPath, which might require affected applications to adapt.

    Check the newer update, KB5044035

    Key changes 1 CVE · 4 changes

    • Improved System.IO.Path.GetTempPath: Some applications might get a different temporary-folder path. Affected software is expected to change its code to adapt.
    • Fix .NET Framework: An elevation-of-privilege vulnerability in .NET Framework is addressed.
    • Fix Winforms: An issue with memory leaks involving AccessibleObjects held in memory is addressed.

    Read update Source: Microsoft

    Builds
    4.8.9256.0 · 2.0.50727.9177
    Security
    1 vulnerability fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows 10 21H2, 22H2 Security update

    KB5039884

    Addresses elevation flaw; temp paths change where GetTempPath2 exists

    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.

    Check the newer update, KB5044020

    Key changes 1 CVE · 3 changes

    • Improved 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 p...
    • Fix .NET Framework: The update addresses a security vulnerability in .NET Framework.
    • Fix Winforms: Memory leaks linked to WinForms accessibility objects are addressed.

    Read update Source: Microsoft

    Builds
    4.8.4739.0 · 2.0.50727.9177
    Security
    1 vulnerability fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows Server 2022 Security update

    KB5039889

    WinForms memory leaks reduced; privilege escalation addressed

    Addresses an elevation-of-privilege vulnerability and reduces WinForms memory leaks. The security fix also changes temporary-path results for SYSTEM processes on Windows versions that expose GetTempPath2.

    Check the newer update, KB5044025

    Key changes 1 CVE · 2 changes

    • Fix .NET Framework: An elevation-of-privilege vulnerability is addressed.
    • Fix WinForms: Memory leaks associated with AccessibleObjects held in memory are reduced.
    • Security CVE-2024-38081: .NET, .NET Framework, and Visual Studio Elevation of Privilege Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.4739.0 · 2.0.50727.9177
    Security
    1 vulnerability fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows 10 1809 · Windows Server 2019 Security update

    KB5039886

    Temporary-folder paths change; WinForms memory leaks addressed

    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.

    Check the newer update, KB5044022

    Key changes 1 CVE · 3 changes

    • Improved System.IO.Path.GetTempPath: Some applications may get a different temporary-folder path after the security fix. Affected software is expected to adapt to the new b...
    • Fix .NET Framework: The update addresses CVE-2024-38081, a security vulnerability in .NET Framework.
    • Fix Winforms: The size of memory leaks involving WinForms accessibility objects held in memory is addressed.

    Read update Source: Microsoft

    Builds
    4.8.4739.0 · 2.0.50727.9064
    Security
    1 vulnerability fixed
    Restart
    Required
  • .NET Framework 4.8 .NET Framework 4.8 for Windows 10 1607 · Windows Server 2016 Security update

    KB5039885

    System.IO.Path.GetTempPath behavior changes; memory leaks addressed

    The update fixes an elevation-of-privilege vulnerability, changes the temporary-folder path returned by System.IO.Path.GetTempPath for SYSTEM processes, and addresses a Windows Forms memory-leak issue.

    Check the newer update, KB5044021

    Key changes 1 CVE · 3 changes

    • Fix .NET Framework: An elevation-of-privilege vulnerability in .NET Framework is addressed.
    • Fix Windows Forms: The size of memory leaks involving AccessibleObjects held in memory is addressed.
    • Fix System.IO.Path.GetTempPath: The temporary-folder path returned to SYSTEM processes changes to %WINDIR%\SystemTemp, which non-SYSTEM processes cannot access. Affect...

    Read update Source: Microsoft

    Build
    4.8.4739.0
    Security
    1 vulnerability fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.7.2 .NET Framework 3.5 / 4.7.2 for Windows 10 1809 · Windows Server 2019 Security update

    KB5039879

    Temp-path behavior changes to close a privilege flaw

    The update addresses CVE-2024-38081, an elevation-of-privilege vulnerability. It also changes how .NET resolves temporary paths, which may require affected applications to adapt.

    Check the newer update, KB5044016

    Key changes 1 CVE · 2 changes

    • Fix .NET Framework: Addresses an elevation-of-privilege vulnerability.
    • Fix Winforms: Addresses a memory leak associated with AccessibleObjects held in memory.
    • Security CVE-2024-38081: .NET, .NET Framework, and Visual Studio Elevation of Privilege Vulnerability

    Read update Source: Microsoft

    Builds
    4.7.4101.0 · 2.0.50727.9064
    Security
    1 vulnerability fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 10 22H2 Optional preview
    Preview

    KB5039865

    WinForms memory leaks and Azure AD certificate use addressed

    Addresses memory leaks involving Windows Forms accessibility objects and an issue using x509 certificates under PPL in Azure AD. It contains no new security improvements.

    Key changes 2 changes

    • Fix Winforms: Addresses an issue involving the size of memory leaks from accessibility objects held in memory.
    • Fix .NET Fundamentals: Addresses an issue with using x509 certificates under PPL in Azure AD.

    Read update Source: Microsoft

    Builds
    4.8.9251.0 · 2.0.50727.9176
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows 10 22H2 Optional preview
    Preview

    KB5039867

    Windows Forms memory-leak issue addressed

    Addresses a Windows Forms memory-leak issue involving accessibility objects held in memory.

    Key changes 1 change

    • Fix Winforms: Windows Forms addresses a memory-leak issue involving accessibility objects held in memory.

    Read update Source: Microsoft

    Builds
    4.8.4734.0 · 2.0.50727.9176
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows 10 22H2 Optional preview
    Preview

    KB5040370

    Quality and reliability updates for .NET

    Includes cumulative .NET Framework updates for Windows 10 version 22H2. The page points to separate articles for the quality and reliability details.

    Check the newer update, KB5041355

    Key changes 2 changes

    • Improved .NET Framework 3.5 and 4.8: This update includes quality and reliability improvements for .NET Framework 3.5 and 4.8; the page links to an article with details.
    • Improved .NET Framework 3.5 and 4.8.1: This update includes quality and reliability improvements for .NET Framework 3.5 and 4.8.1; the page links to an article with details.

    Read update Source: Microsoft

    Restart
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  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 10 21H2, 22H2 Optional preview
    Preview

    KB5037587

    WPF crashes and CLR query errors addressed

    Addresses reliability issues in .NET Framework, including app crashes in WPF and the CLR. It adds no new security improvements.

    Check the newer update, KB5039893

    Key changes 6 changes

    • Fix CLR: Addresses a problem that can cause crashes when several threads query the same managed type.
    • Fix CLR: Addresses cases where symbol-reading APIs might return incorrect results.
    • Fix .NET Libraries: Addresses an issue that can be triggered in the FBX file parser.

    Read update Source: Microsoft

    Builds
    4.8.9241.0 · 2.0.50727.9176
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows Server 2022 Update

    KB5037929

    WPF window-text crashes and .NET runtime errors addressed

    Apps that read window text can crash, and some SQL CLR apps can hit runtime errors with specific hash types. This update also addresses issues in IIS 10 and .NET libraries.

    Check the newer update, KB5039907

    Key changes 6 changes

    • Fix CLR: Crashes from simultaneous queries of the same managed type are addressed.
    • Fix CLR: Two APIs that find methods by document position can return incorrect results in some cases; this issue is addressed.
    • Fix .NET Libraries: An issue in the FBX file parser is addressed.

    Read update Source: Microsoft

    Builds
    4.8.9246.0 · 2.0.50727.9176
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows 10 21H2, 22H2 Optional preview
    Preview

    KB5037592

    WPF app crashes and 32-bit response delays addressed

    Addresses several .NET reliability problems, including some app crashes and slow responses on 32-bit platforms. A restart might be needed if affected files are in use.

    Check the newer update, KB5039884

    Key changes 5 changes

    • Fix CLR: Some apps can crash when multiple background tasks check the same kind of information at the same time.
    • Fix .NET Libraries: The update addresses unusually slow response times on 32-bit platforms.
    • Fix .NET Libraries: The update addresses how .NET chooses validated methods for security-related calculations.

    Read update Source: Microsoft

    Builds
    4.8.4724.0 · 2.0.50727.9176
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows Server 2022 Update

    KB5037930

    WPF app crashes and concurrent type-query failures addressed

    Concurrent type queries can crash the .NET runtime, and WPF apps can crash when reading window text. A later update, KB5043743, resolves a separate SQL CLR runtime exception.

    Check the newer update, KB5039889

    Key changes 5 changes

    • Fix CLR: Concurrent checks of the same managed type can crash the runtime; this update addresses the problem.
    • Fix .NET Libraries: Some 32-bit platforms can have much slower response times; this update addresses the slowdown.
    • Fix .NET Libraries: The update addresses an issue with using MIST-validated FIPS algorithms.

    Read update Source: Microsoft

    Builds
    4.8.4729.0 · 2.0.50727.9176
    Restart
    Required
  • .NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 for Windows 10 1809 · Windows Server 2019 Update

    KB5037933

    Three SQL CLR hash constructors trigger errors; later fixed

    Runtime exceptions can occur in SQL CLR code that creates SHA256Managed, SHA384Managed, or SHA512Managed objects; KB5043804 resolves the issue. The update also addresses .NET reliability problems.

    Check the newer update, KB5039886

    Key changes 5 changes

    • Fix CLR: Crashes can occur when several threads query the same managed type at once. The update addresses this issue.
    • Fix .NET Libraries: Some 32-bit devices can have much slower response times. The update addresses this issue.
    • Fix .NET Libraries: The update addresses an issue with validated FIPS algorithm implementations.

    Read update Source: Microsoft

    Builds
    4.8.4729.0 · 2.0.50727.9063
    Restart
    Required
  • .NET Framework 4.8 .NET Framework 4.8 for Windows 10 1607 · Windows Server 2016 Update

    KB5037926

    Crashes from concurrent ITypeInfo queries on one managed type addressed

    When several threads query one managed type's ITypeInfo at once, crashes can occur; this update addresses that case. It also addresses a major response-time slowdown on 32-bit platforms.

    Check the newer update, KB5039885

    Key changes 5 changes

    • Fix CLR: Crashes can occur when several threads query the same managed type at once; this update addresses that case.
    • Fix .NET Libraries: The update addresses a major response-time slowdown on 32-bit platforms.
    • Fix .NET Libraries: The update addresses an issue with how certain security algorithms are used.

    Read update Source: Microsoft

    Build
    4.8.4729.0
    Restart
    Required
  • .NET Framework 3.5 / 4.7.2 .NET Framework 3.5 / 4.7.2 for Windows 10 1809 · Windows Server 2019 Update

    KB5037932

    Concurrent .NET crashes and 32-bit response delays addressed

    The update addresses possible .NET runtime crashes during concurrent type queries and a response-time regression on 32-bit platforms. You must restart the computer after applying it if any affected files are in use.

    Check the newer update, KB5039879

    Key changes 2 changes

    • Fix CLR: Addresses crashes that can occur when several threads query the same managed type at the same time.
    • Fix .NET Libraries: Addresses a significant response-time slowdown on 32-bit platforms.

    Read update Source: Microsoft

    Builds
    4.7.4095.0 · 2.0.50727.9063
    Restart
    Required