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

KB5101001

KB5101001: Cumulative update for .NET Framework, versions 3.5 and 4.8.1, on Windows 11 24H2, July 2026. Runtime flaws addressed; secure requests and debugging improved

In short

The update addresses 17 important vulnerabilities. It also addresses hangs in some secure web requests and wrong values in Visual Studio debugging.

Does it affect you? Applies to: Devices running Windows 11, version 24H2, with .NET Framework 3.5 or 4.8.1 installed.

File version
2.0.50727.9182 · 4.8.9339.0
Security
17 fixed
Restart
Required

What changes

Fixes 19 changes

.NET Framework

17 items
  • A flaw could let someone disrupt a service.1
    Addresses the denial of service vulnerability CVE-2026-47302.
  • A flaw could let someone get around a security feature.2
    Addresses the security feature bypass vulnerability CVE-2026-47304.
  • A flaw could let someone disrupt a service.3
    Addresses the denial of service vulnerability CVE-2026-50304.
  • A flaw could let someone disrupt a service.4
    Addresses the denial of service vulnerability CVE-2026-50324.
  • A flaw could let someone disrupt a service.5
    Addresses the denial of service vulnerability CVE-2026-50355.
  • A flaw could let someone disrupt a service.6
    Addresses the denial of service vulnerability CVE-2026-50368.
  • A flaw could let someone disrupt a service.7
    Addresses the denial of service vulnerability CVE-2026-50411.
  • A flaw could let someone disrupt a service.8
    Addresses the denial of service vulnerability CVE-2026-50525.
  • A flaw could let someone disrupt a service.9
    Addresses the denial of service vulnerability CVE-2026-50527.
  • A flaw could let someone gain more access.10
    Addresses the elevation of privilege vulnerability CVE-2026-50646.
  • A flaw could let someone disrupt a service.11
    Addresses the denial of service vulnerability CVE-2026-50647.
  • A flaw could let someone disrupt a service.12
    Addresses the denial of service vulnerability CVE-2026-50648.
  • A flaw could let someone run code from another computer.13
    Addresses the remote code execution vulnerability CVE-2026-50649.
  • A flaw could let someone gain more access.14
    Addresses the elevation of privilege vulnerability CVE-2026-50650.
  • A flaw could let someone disrupt a service.15
    Addresses the denial of service vulnerability CVE-2026-50652.
  • A flaw could let someone disrupt a service.16
    Addresses the denial of service vulnerability CVE-2026-50653.
  • A flaw could let someone change data.17
    Addresses the tampering vulnerability CVE-2026-50659.

.NET Libraries

  • Addresses hangs in some secure web requests.18
    Addresses an issue with synchronous HttpWebRequest connections that could hang in some secure connection scenarios with certain server configurations.

.NET Runtime

  • Addresses wrong values shown during some Visual Studio debugging steps.19
    Addresses incorrect floating-point values reported by the Visual Studio x86 native debugger during step operations in mixed-code applications.

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
KB5092430, KB5087054, KB5082420, KB5074831
+9 earlier KB5066131, KB5064401, KB5056579, KB5054979, KB5050577, KB5049622, KB5048162, KB5045934, KB5044030
Replaced by
KB5120710
VersionFile versionChannel
3.5 2.0.50727.9182 General availability
4.8.1 4.8.9339.0 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

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 5/5, 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