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.NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 Security update
Patch Tuesday

KB5100998

KB5100998: Cumulative update for .NET Framework, versions 3.5 and 4.8.1, on Windows 11 25H2 and Windows Server 2025, July 2026. Remote-code execution flaw among 17 vulnerabilities addressed

In short

Addresses 17 Important .NET vulnerabilities, including a remote-code execution flaw, and two reliability issues. None are rated Critical or known to be publicly disclosed or exploited.

Does it affect you? Applies to: Devices running Windows 11, version 25H2, or Windows Server 2025 (Microsoft server operating system 24H2) with .NET Framework 3.5 or 4.8.1 installed.

File version
2.0.50727.9182 · 4.8.9340.0
Security
17 fixed
Restart
Required

What changes

Fixes 19 changes

.NET Framework

17 items
  • The update addresses a security flaw that could cause denial of service.1
    CVE-2026-47302.
  • The update addresses a security feature bypass flaw.2
    CVE-2026-47304.
  • The update addresses a security flaw that could cause denial of service.3
    CVE-2026-50304.
  • The update addresses a security flaw that could cause denial of service.4
    CVE-2026-50324.
  • The update addresses a security flaw that could cause denial of service.5
    CVE-2026-50355.
  • The update addresses a security flaw that could cause denial of service.6
    CVE-2026-50368.
  • The update addresses a security flaw that could cause denial of service.7
    CVE-2026-50411.
  • The update addresses a security flaw that could cause denial of service.8
    CVE-2026-50525.
  • The update addresses a security flaw that could cause denial of service.9
    CVE-2026-50527.
  • The update addresses a flaw that could allow elevation of privilege.10
    CVE-2026-50646.
  • The update addresses a security flaw that could cause denial of service.11
    CVE-2026-50647.
  • The update addresses a security flaw that could cause denial of service.12
    CVE-2026-50648.
  • The update addresses a flaw that could allow remote code execution.13
    CVE-2026-50649.
  • The update addresses a flaw that could allow elevation of privilege.14
    CVE-2026-50650.
  • The update addresses a security flaw that could cause denial of service.15
    CVE-2026-50652.
  • The update addresses a security flaw that could cause denial of service.16
    CVE-2026-50653.
  • The update addresses a tampering flaw.17
    CVE-2026-50659.

.NET Libraries

  • Addresses an issue that could make some synchronous web requests hang in specific secure connection scenarios.18
    The issue involves synchronous HttpWebRequest connections and certain server configurations.

.NET Runtime

  • Addresses an issue where the Visual Studio x86 debugger could report some floating-point values incorrectly while stepping through mixed-code applications.19
    The issue affects the Visual Studio x86 native debugger during step operations.

Technical details

Data sheet · Security · Downloads · Components Click to collapse or expand

Data sheet

Released
2026-07-14
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5092427, KB5087051, KB5082417, KB5074828
+10 earlier KB5067931, KB5066128, KB5066131, KB5066613, KB5064401, KB5056579, KB5054979, KB5049622, KB5045934, KB5044030
Replaced by
KB5120708
VersionFile versionChannel
3.5 2.0.50727.9182 General availability
4.8.1 4.8.9340.0 General availability

Security

17 vulnerabilities fixed
17 important
VulnerabilitySeverityCVSS
CVE-2026-47304
.NET Security Feature Bypass Vulnerability
 Important 8.1
CVE-2026-50646
.NET Framework Remote Code Execution Vulnerability
 Important 7.8
CVE-2026-50649
.NET Remote Code Execution Vulnerability
 Important 7.8
CVE-2026-50650
.NET Framework Elevation of Privilege Vulnerability
 Important 7.8
CVE-2026-47302
.NET Denial of Service Vulnerability
 Important 7.5
CVE-2026-50304
Windows Active Directory Federation Services Denial of Service Vulnerability
 Important 7.5
CVE-2026-50355
Windows Active Directory Federation Services Denial of Service Vulnerability
 Important 7.5
CVE-2026-50368
Windows Active Directory Federation Services Denial of Service Vulnerability
 Important 7.5
CVE-2026-50411
Windows Active Directory Federation Services Denial of Service Vulnerability
 Important 7.5
CVE-2026-50525
.NET Denial of Service Vulnerability
 Important 7.5
CVE-2026-50527
.NET Framework Denial of Service Vulnerability
 Important 7.5
CVE-2026-50647
Active Directory Federation Server Denial of Service Vulnerability
 Important 7.5
CVE-2026-50648
.NET Framework Denial of Service Vulnerability
 Important 7.5
CVE-2026-50652
Azure Active Directory Denial of Service Vulnerability
 Important 7.5
CVE-2026-50653
Azure Active Directory Denial of Service Vulnerability
 Important 7.5
CVE-2026-50659
.NET Spoofing Vulnerability
 Important 6.5
CVE-2026-50324
Windows Active Directory Federation Services Denial of Service Vulnerability
 Important 5.9

Downloads (Microsoft Update Catalog)

x64 Windows Server 2025 / Windows 11, version 25H2
92.2 MB
windows11.0-kb5100998-x64-ndp481.msu Main update · KB5100998 SHA-1: 339c932f…5778b7
Arm64 Windows Server 2025 / Windows 11, version 25H2
110.6 MB
windows11.0-kb5100998-arm64-ndp481.msu Main update · KB5100998 SHA-1: 1140f8a7…cf4d22

Updated components

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

Top changed componentsFiles
WPF28
WCF14
.NET runtime (CLR)12
.NET networking6
.NET data access2

Sources

Updated
Cited passages from Microsoft's official notes (19)
  1. 1. This security update addresses a denial of service vulnerability detailed in CVE-2026-47302. support.microsoft.com
  2. 2. This security update addresses a security feature bypass vulnerability detailed in CVE-2026-47304. support.microsoft.com
  3. 3. This security update addresses a denial of service vulnerability detailed in CVE-2026-50304. support.microsoft.com
  4. 4. This security update addresses a denial of service vulnerability detailed in CVE-2026-50324. support.microsoft.com
  5. 5. This security update addresses a denial of service vulnerability detailed in CVE-2026-50355. support.microsoft.com
  6. 6. This security update addresses a denial of service vulnerability detailed in CVE-2026-50368. support.microsoft.com
  7. 7. This security update addresses a denial of service vulnerability detailed in CVE-2026-50411. support.microsoft.com
  8. 8. This security update addresses a denial of service vulnerability detailed in CVE-2026-50525. support.microsoft.com
  9. 9. This security update addresses a denial of service vulnerability detailed in CVE-2026-50527. support.microsoft.com
  10. 10. This security update addresses an elevation of privilege vulnerability detailed in CVE-2026-50646. support.microsoft.com
  11. 11. This security update addresses a denial of service vulnerability detailed in CVE-2026-50647. support.microsoft.com
  12. 12. This security update addresses a denial of service vulnerability detailed in CVE-2026-50648. support.microsoft.com
  13. 13. This security update addresses a remote code execution vulnerability detailed in CVE-2026-50649. support.microsoft.com
  14. 14. This security update addresses an elevation of privilege vulnerability detailed in CVE-2026-50650. support.microsoft.com
  15. 15. This security update addresses a denial of service vulnerability detailed in CVE-2026-50652. support.microsoft.com
  16. 16. This security update addresses a denial of service vulnerability detailed in CVE-2026-50653. support.microsoft.com
  17. 17. This security update addresses a tampering vulnerability detailed in CVE-2026-50659. support.microsoft.com
  18. 18. Addresses an issue with synchronous HttpWebRequest connections where requests could hang in specific secure connection scenarios with certain server configurations. support.microsoft.com
  19. 19. Addresses an issue in the Visual Studio x86 native debugger where certain floating-point values could be reported incorrectly during step operations in mixed-code applications. support.microsoft.com
Checked automatically: 7 of 8 checks passed, 19 quoted passages · compared with Microsoft's page on Sep 25, 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 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