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.NET Framework 4.8.1

.NET Framework 4.8.1

Every published release for .NET Framework 4.8.1, newest first: what each update changes, whether to install it and any confirmed known issues.

Latest
KB5127694 Oct 13, 2026
File version
4.8.10008.0
Released
Aug 9, 2022
Known issues
1 open

Update history

  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 26H1 Optional preview
    Preview

    KB5092431

    HttpWebRequest hangs and x86 debugger values corrected

    Addresses cases where secure web requests hang and where Visual Studio's x86 debugger reports some floating-point values incorrectly.

    Check the newer update, KB5101002

    Key changes 2 changes

    • Fix .NET Libraries: The update addresses cases where secure web requests could hang with certain server configurations.
    • Fix .NET Runtime: The update addresses cases where some floating-point values could be reported incorrectly while stepping through mixed-code application...

    Read update Source: Microsoft

    Build
    4.8.9337.0
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 25H2 Optional preview
    Preview

    KB5092427

    Hanging secure requests and incorrect debugger values addressed

    Addresses hanging synchronous web requests in certain secure-connection setups and incorrect floating-point values in Visual Studio’s x86 native debugger.

    Check the newer update, KB5100998

    Key changes 2 changes

    • Fix .NET Libraries: Synchronous web requests are less likely to hang in certain secure-connection setups.
    • Fix .NET Runtime: Some floating-point values are reported more accurately when stepping through mixed-code applications in the Visual Studio x86 native d...

    Read update Source: Microsoft

    Builds
    4.8.9337.0 · 2.0.50727.9181
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 24H2 Optional preview
    Preview

    KB5092430

    Hanging secure requests and debugger values addressed

    Addresses cases where secure HTTP requests could hang and floating-point values could be reported incorrectly in Visual Studio’s x86 native debugger.

    Check the newer update, KB5101001

    Key changes 2 changes

    • Fix .NET Libraries: Some requests over secure connections could hang with certain server setups; this update addresses the issue.
    • Fix .NET Runtime: Floating-point values could be reported incorrectly while stepping through code in Visual Studio’s x86 native debugger; this update add...

    Read update Source: Microsoft

    Builds
    4.8.9336.0 · 2.0.50727.9181
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 26H1 Security update

    KB5087055

    Two framework flaws could allow higher access

    Addresses two .NET Framework flaws that could let someone gain higher access: CVE-2026-32177 and CVE-2026-35433.

    Check the newer update, KB5101002

    Key changes 2 CVEs · 2 changes

    • Fix .NET Framework: A flaw could let someone gain higher access.
    • Fix .NET Framework: A flaw could let someone gain higher access.
    • CVSS 7.3 CVE-2026-32177: .NET Elevation of Privilege Vulnerability

    Read update Source: Microsoft

    Build
    4.8.9335.0
    Security
    2 vulnerabilities fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 25H2 · Windows Server 2025 Security update

    KB5087051

    Two framework flaws could let someone gain higher access

    The update fixes two .NET Framework flaws that could let someone gain higher access. It installs through Windows Update and needs a restart if affected files are in use.

    Check the newer update, KB5100998

    Key changes 2 CVEs · 2 changes

    • Fix .NET Framework: A flaw that could let someone gain higher access is addressed.
    • Fix .NET Framework: A flaw that could let someone gain higher access is addressed.
    • CVSS 7.3 CVE-2026-32177: .NET Elevation of Privilege Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.9335.0 · 2.0.50727.9181
    Security
    2 vulnerabilities fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 24H2 Security update

    KB5087054

    Two .NET privilege flaws addressed

    Addresses two Important .NET Framework security flaws. Both could let someone gain higher access than intended.

    Check the newer update, KB5101001

    Key changes 2 CVEs · 2 changes

    • Improved .NET Framework: A security flaw could let someone gain higher access than intended.
    • Improved .NET Framework: A security flaw could let someone gain higher access than intended.
    • CVSS 7.3 CVE-2026-32177: .NET Elevation of Privilege Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.9334.0 · 2.0.50727.9181
    Security
    2 vulnerabilities fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 23H2 Security update

    KB5087058

    Runtime elevation-of-privilege flaws addressed

    Two .NET Framework elevation-of-privilege vulnerabilities, CVE-2026-32177 and CVE-2026-35433, are addressed. A restart is required if affected files are in use.

    Check the newer update, KB5101004

    Key changes 2 CVEs · 2 changes

    • Fix .NET Framework: An elevation-of-privilege security vulnerability tracked as CVE-2026-32177 is addressed.
    • Fix .NET Framework: An elevation-of-privilege security vulnerability tracked as CVE-2026-35433 is addressed.
    • CVSS 7.3 CVE-2026-32177: .NET Elevation of Privilege Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.9334.0 · 2.0.50727.9181
    Security
    2 vulnerabilities fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 10 21H2, 22H2 Security update

    KB5087053

    Two .NET runtime elevation-of-privilege flaws addressed

    The update addresses two elevation-of-privilege vulnerabilities in .NET Framework 3.5 and 4.8.1. A restart might be required if affected files are in use.

    Check the newer update, KB5101000

    Key changes 2 CVEs · 2 changes

    • Fix .NET Framework: The update addresses an elevation-of-privilege vulnerability in .NET Framework.
    • Fix .NET Framework: The update addresses an elevation-of-privilege vulnerability in .NET Framework.
    • CVSS 7.3 CVE-2026-32177: .NET Elevation of Privilege Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.9334.0 · 2.0.50727.9181
    Security
    2 vulnerabilities fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows Server 2022 Security update

    KB5087059

    Two flaws could give attackers more access

    Addresses two important security flaws in .NET Framework. It applies to Windows Server 2022 devices with .NET Framework 3.5 or 4.8.1 installed.

    Check the newer update, KB5101005

    Key changes 2 CVEs · 2 changes

    • Improved .NET Framework: Addresses a security flaw that could let an attacker gain more access.
    • Improved .NET Framework: Addresses a security flaw that could let an attacker gain more access.
    • CVSS 7.3 CVE-2026-32177: .NET Elevation of Privilege Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.9334.0 · 2.0.50727.9181
    Security
    2 vulnerabilities fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 26H1 Security update

    KB5082421

    Critical denial-of-service flaw addressed; WCF issue fixed

    The update addresses six .NET Framework vulnerabilities, including one critical denial-of-service flaw, and a problem running WCF NamedPipe services in Win32 app containers.

    Check the newer update, KB5087055

    Key changes 6 CVEs · 7 changes

    • Fix .NET Framework: Addresses a remote code execution vulnerability in .NET Framework.
    • Fix .NET Framework: Addresses a denial-of-service vulnerability in .NET Framework.
    • Fix .NET Framework: Addresses a denial-of-service vulnerability in .NET Framework.

    Read update Source: Microsoft

    Builds
    4.8.9333.0 · 2.0.50727.9181
    Security
    6 fixed · 1 critical
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 25H2 · Windows Server 2025 Security update

    KB5082417

    WCF service issue in app containers addressed

    Addresses a .NET Framework issue affecting local communication services in some Windows apps, and fixes six vulnerabilities, including one critical denial-of-service flaw.

    Check the newer update, KB5087051

    Key changes 6 CVEs · 1 change

    • Fix WCF: An issue affecting local communication services in Windows apps running in an isolated app container is addressed.
    • Critical CVE-2026-23666: .NET Framework Denial of Service Vulnerability
    • CVSS 7.5 CVE-2026-33116: .NET, .NET Framework, and Visual Studio Denial of Service Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.9333.0 · 2.0.50727.9181
    Security
    6 fixed · 1 critical
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 24H2 Security update

    KB5082420

    Runtime denial-of-service flaw addressed; app-container service fixed

    The update addresses six vulnerabilities, including a critical denial-of-service flaw, and addresses a problem running a Windows communication service in an app's restricted environment.

    Check the newer update, KB5087054

    Key changes 6 CVEs · 7 changes

    • Fix .NET Framework: A flaw that could allow code to run remotely is addressed.
    • Fix .NET Framework: A flaw that could disrupt service availability is addressed.
    • Fix .NET Framework: A flaw that could disrupt service availability is addressed.

    Read update Source: Microsoft

    Builds
    4.8.9332.0 · 2.0.50727.9181
    Security
    6 fixed · 1 critical
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 23H2 Security update

    KB5082424

    Critical denial-of-service flaw addressed; ARM runtime crash improved

    The update addresses six .NET Framework vulnerabilities, including one critical denial-of-service flaw, and improves reliability for ClickOnce checks, ARM devices, and WCF services.

    Check the newer update, KB5087058

    Key changes 6 CVEs · 9 changes

    • Improved .NET Runtime: Checks for ClickOnce apps can now use two additional methods to verify files.
    • Fix .NET Framework: A flaw that could let an attacker run code remotely is addressed.
    • Fix .NET Framework: A flaw that could make a service unavailable is addressed.

    Read update Source: Microsoft

    Builds
    4.8.9332.0 · 2.0.50727.9181
    Security
    6 fixed · 1 critical
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 10 21H2, 22H2 Security update

    KB5082419

    Six security flaws addressed; ARM runtime crash fixed

    Addresses six .NET Framework vulnerabilities, including one critical denial-of-service flaw, and fixes an ARM64 runtime crash. Installation might fail through DISM on an offline Windows 10 IoT Enterprise LTSC 21H2 image.

    Check the newer update, KB5087053

    Key changes 6 CVEs · 9 changes

    • Fix .NET Framework: Addresses a remote code execution vulnerability.
    • Fix .NET Framework: Addresses a denial-of-service vulnerability.
    • Fix .NET Framework: Addresses a denial-of-service vulnerability.

    Read update Source: Microsoft

    Builds
    4.8.9332.0 · 2.0.50727.9181
    Security
    6 fixed · 1 critical
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows Server 2022 Security update

    KB5082425

    Critical denial-of-service flaw addressed; ARM64 runtime crash improved

    The update addresses six vulnerabilities, including a critical .NET Framework denial-of-service flaw, and reliability issues in ClickOnce, the ARM64 runtime, and WCF.

    Check the newer update, KB5087059

    Key changes 6 CVEs · 3 changes

    • Fix .NET Runtime: ClickOnce gains verification logic for SHA384 and SHA512.
    • Fix .NET Runtime: Addresses an issue that could make the .NET runtime crash on ARM64 when code generates and catches a NullReferenceException in the same...
    • Fix WCF: Addresses an issue with WCF NamedPipe services running inside a Win32 app container on Windows 11 or Windows Server 2025.

    Read update Source: Microsoft

    Builds
    4.8.9332.0 · 2.0.50727.9181
    Security
    6 fixed · 1 critical
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 26H1 Security update

    KB5074837

    .NET information disclosure flaw and runtime issues addressed

    The update addresses CVE-2025-55248, an information disclosure vulnerability, and three .NET Runtime reliability issues, including a possible crash on Arm64.

    Check the newer update, KB5082421

    Key changes 1 CVE · 4 changes

    • Improved .NET Runtime: ClickOnce verification supports SHA384 and SHA512.
    • Fix .NET Framework: Addresses an information disclosure vulnerability in .NET Framework.
    • Fix .NET Runtime: Updates operating system calls to comply with current standards.

    Read update Source: Microsoft

    Build
    4.8.9325.0
    Security
    1 vulnerability fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 25H2 Optional preview
    Preview

    KB5074828

    ClickOnce gains SHA384 and SHA512 checks; ARM64 CLR crash addressed

    Adds SHA384 and SHA512 verification support for ClickOnce and addresses a case where the .NET runtime could crash on ARM64 devices.

    Check the newer update, KB5082417

    Key changes 2 changes

    • Improved .NET Runtime: ClickOnce verification supports SHA384 and SHA512.
    • Fix .NET Runtime: The update addresses a case where the .NET runtime could crash on ARM64 devices.

    Read update Source: Microsoft

    Builds
    4.8.9325.0 · 2.0.50727.9180
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 24H2 Optional preview
    Preview

    KB5074831

    ClickOnce hash checks added; arm64 runtime crash addressed

    Adds ClickOnce verification for SHA384 and SHA512 and addresses an issue that could crash the .NET runtime on arm64 devices.

    Check the newer update, KB5082420

    Key changes 2 changes

    • Fix .NET Runtime: ClickOnce verification gains support for SHA384 and SHA512.
    • Fix .NET Runtime: On arm64 devices, the .NET runtime could crash when code generates and catches a null-reference exception in the same function; this up...

    Read update Source: Microsoft

    Builds
    4.8.9324.0 · 2.0.50727.9180
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 25H2 Optional preview
    Preview

    KB5067931

    .NET Runtime calls updated to meet current standards

    The preview updates .NET Runtime operating-system calls for compliance with current standards. It adds no new security improvements.

    Check the newer update, KB5074828

    Key changes 1 change

    • Improved .NET Runtime: Operating-system calls are updated to comply with current standards.

    Read update Source: Microsoft

    Builds
    4.8.9323.0 · 2.0.50727.9180
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 25H2 Security update

    KB5066128

    Information exposure flaw fixed in .NET

    Fixes a flaw that could expose information in .NET Framework. It applies to Windows 11 version 25H2 with .NET Framework 3.5 or 4.8.1 installed.

    Check the newer update, KB5082417

    Key changes 1 CVE · 1 change

    • Fix .NET Framework: A flaw that could expose information is fixed.
    • CVSS 4.8 CVE-2025-55248: .NET, .NET Framework, and Visual Studio Information Disclosure Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.9321.0 · 2.0.50727.9180
    Security
    1 vulnerability fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 24H2 · Windows Server 2025 Security update

    KB5066131

    Information disclosure flaw in the managed runtime addressed

    The update addresses one Important-severity information disclosure vulnerability in .NET Framework: CVE-2025-55248.

    Check the newer update, KB5082417

    Key changes 1 CVE · 1 change

    • Fix .NET Framework: An information disclosure vulnerability is addressed.
    • CVSS 4.8 CVE-2025-55248: .NET, .NET Framework, and Visual Studio Information Disclosure Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.9320.0 · 2.0.50727.9180
    Security
    1 vulnerability fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 11 23H2 Security update

    KB5066133

    Information exposure flaw addressed in framework libraries

    Addresses a flaw that could expose information in .NET Framework 3.5 and 4.8.1. Windows Update installs it automatically.

    Check the newer update, KB5082424

    Key changes 1 CVE · 1 change

    • Fix .NET Framework: The update addresses a flaw that could expose information.
    • CVSS 4.8 CVE-2025-55248: .NET, .NET Framework, and Visual Studio Information Disclosure Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.9320.0 · 2.0.50727.9180
    Security
    1 vulnerability fixed
    Restart
    Required
  • .NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 for Windows 10 21H2, 22H2 Security update

    KB5066130

    Information disclosure flaw in the application runtime addressed

    The update addresses CVE-2025-55248, an information disclosure vulnerability in .NET Framework. Restart your computer if affected files are in use.

    Check the newer update, KB5082419

    Key changes 1 CVE · 1 change

    • Fix .NET Framework: An information disclosure vulnerability in .NET Framework is addressed.
    • Security CVE-2025-55248: .NET, .NET Framework, and Visual Studio Information Disclosure Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.9320.0 · 2.0.50727.9180
    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

    KB5066134

    Information disclosure vulnerability addressed

    The update addresses CVE-2025-55248, an information disclosure vulnerability in .NET Framework 3.5 and 4.8.1 on Windows Server 2022.

    Check the newer update, KB5082425

    Key changes 1 CVE · 1 change

    • Fix .NET Framework: An information disclosure vulnerability is addressed.
    • Security CVE-2025-55248: .NET, .NET Framework, and Visual Studio Information Disclosure Vulnerability

    Read update Source: Microsoft

    Builds
    4.8.9320.0 · 2.0.50727.9180
    Security
    1 vulnerability fixed
    Restart
    Required