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

KB5127692

KB5127692: Cumulative update for .NET Framework, versions 3.5 and 4.8.1, on Windows 11 23H2, October 2026. Critical spoofing flaw and disclosed security bypass addressed

In short

The update addresses 21 vulnerabilities, including one critical flaw and a publicly disclosed security bypass. It also updates .NET Framework 3.5 and 4.8.1.

Does it affect you? Applies to: Devices running Windows 11, version 23H2, with .NET Framework 3.5 or 4.8.1 installed. Packages are available for x64 and Arm64 devices.

File version
2.0.50727.9188 · 4.8.9363.0
Security
21 fixed · 1 critical
Restart
Required
Review notes Additional details from the official release notes (1) Read note
  • In detail Microsoft's KB identifies CVE-2026-96222 as a .NET Framework spoofing vulnerability.

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

What changes

Fixes 19 changes

.NET Framework

19 items

For: Devices with .NET Framework installed

  • A flaw that could stop a .NET app from responding is addressed.1
    CVE-2026-58280: .NET Framework denial of service vulnerability.
  • A flaw that could let someone gain more control is addressed.2
    CVE-2026-69439: .NET Framework elevation of privilege vulnerability.
  • A flaw that could stop a .NET app from responding is addressed.3
    CVE-2026-69651: .NET Framework denial of service vulnerability.
  • A flaw that could let an attacker run code is addressed.4
    CVE-2026-70007: .NET Framework remote code execution vulnerability.
  • A flaw that could let an attacker run code is addressed.5
    CVE-2026-70035: .NET Framework remote code execution vulnerability.
  • A flaw that could let an attacker run code is addressed.6
    CVE-2026-70174: .NET Framework remote code execution vulnerability.
  • A flaw that could let an attacker run code is addressed.7
    CVE-2026-83520: .NET Framework remote code execution vulnerability.
  • A flaw that could stop a .NET app from responding is addressed.8
    CVE-2026-84008: .NET Framework denial of service vulnerability.
  • A flaw that could let someone gain more control is addressed.9
    CVE-2026-85363: .NET Framework elevation of privilege vulnerability.
  • A flaw that could let an attacker run code is addressed.10
    CVE-2026-87697: .NET Framework remote code execution vulnerability.
  • A flaw that could let someone fake trusted information is addressed.11
    CVE-2026-96222: .NET Framework spoofing vulnerability.
  • A flaw that could let an attacker run code is addressed.12
    CVE-2026-96224: .NET Framework remote code execution vulnerability.
  • A flaw that could stop a .NET app from responding is addressed.13
    CVE-2026-96233: .NET Framework denial of service vulnerability.
  • A flaw that could stop a .NET app from responding is addressed.14
    CVE-2026-96958: .NET Framework denial of service vulnerability.
  • A flaw that could stop a .NET app from responding is addressed.15
    CVE-2026-96959: .NET Framework denial of service vulnerability.
  • A flaw that could stop a .NET app from responding is addressed.16
    CVE-2026-96960: .NET Framework denial of service vulnerability.
  • A flaw that could expose information is addressed.17
    CVE-2026-97788: .NET Framework information disclosure vulnerability.
  • A flaw that could let someone change data is addressed.18
    CVE-2026-97801: .NET Framework tampering vulnerability.
  • A flaw that could bypass a .NET security feature is addressed.19
    CVE-2026-108398: .NET Framework security feature bypass vulnerability.

Technical details

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

Data sheet

Released
2026-10-13
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5126424, KB5120713, KB5101004, KB5087058
+5 earlier KB5082424, KB5066133, KB5064403, KB5056580, KB5049624
VersionFile versionChannel
3.5 2.0.50727.9188 General availability
4.8.1 4.8.9363.0 General availability

Security

21 vulnerabilities fixed
1 critical 18 important 2 not rated
VulnerabilitySeverityCVSS
CVE-2026-96222
Active Directory Federation Services (AD FS) Spoofing Vulnerability
 Critical 7.4
CVE-2026-102869
.NET and Visual Studio Elevation of Privilege Vulnerability
 Important 8.8
CVE-2026-108398
.NET Framework Security Feature Bypass Vulnerability
 Important 8.8
CVE-2026-70007
.NET Framework Remote Code Execution Vulnerability
 Important 8.8
CVE-2026-70035
.NET Framework Remote Code Execution Vulnerability
 Important 8.8
CVE-2026-70174
.NET Remote Code Execution Vulnerability
 Important 8.8
CVE-2026-83520
.NET Remote Code Execution Vulnerability
 Important 8.8
CVE-2026-85363
.NET Framework Elevation of Privilege Vulnerability
 Important 8.8
CVE-2026-96224
.NET Remote Code Execution Vulnerability
 Important 8.8
CVE-2026-62886
.NET Elevation of Privilege Vulnerability
 Important 7.8
CVE-2026-58280
.NET Denial of Service Vulnerability
 Important 7.5
CVE-2026-69651
.NET Denial of Service Vulnerability
 Important 7.5
CVE-2026-84008
.NET Denial of Service Vulnerability
 Important 7.5
CVE-2026-96233
ASP.NET Core Denial of Service Vulnerability
 Important 7.5
CVE-2026-96958
.NET Denial of Service Vulnerability
 Important 7.5
CVE-2026-96959
.NET Denial of Service Vulnerability
 Important 7.5
CVE-2026-96960
.NET Denial of Service Vulnerability
 Important 7.5
CVE-2026-97788
Active Directory Federation Services (AD FS) Information Disclosure Vulnerability
 Important 7.5
CVE-2026-97801
.NET Framework Tampering Vulnerability
 Important 7.5
CVE-2026-69439
.NET and Visual Studio Elevation of Privilege Vulnerability
 Not rated —
CVE-2026-87697
.NET Remote Code Execution Vulnerability
 Not rated —

Updated components

1,262 files changed since the previous update for the same versions.

Top changed componentsFiles
ASP.NET81
WPF81
WCF66
.NET networking42
.NET data access33
.NET runtime (CLR)33
Windows Forms12

Sources

Updated
Cited passages from Microsoft's official notes (19)
  1. 1. This security update addresses a denial of service vulnerability detailed in CVE-2026-58280. support.microsoft.com
  2. 2. This security update addresses an elevation of privilege vulnerability detailed in CVE-2026-69439. support.microsoft.com
  3. 3. This security update addresses a denial of service vulnerability detailed in CVE-2026-69651. support.microsoft.com
  4. 4. This security update addresses a remote code execution vulnerability detailed in CVE-2026-70007. support.microsoft.com
  5. 5. This security update addresses a remote code execution vulnerability detailed in CVE-2026-70035. support.microsoft.com
  6. 6. This security update addresses a remote code execution vulnerability detailed in CVE-2026-70174. support.microsoft.com
  7. 7. This security update addresses a remote code execution vulnerability detailed in CVE-2026-83520. support.microsoft.com
  8. 8. This security update addresses a denial of service vulnerability detailed in CVE-2026-84008. support.microsoft.com
  9. 9. This security update addresses an elevation of privilege vulnerability detailed in CVE-2026-85363. support.microsoft.com
  10. 10. This security update addresses a remote code execution vulnerability detailed in CVE-2026-87697. support.microsoft.com
  11. 11. This security update addresses a spoofing vulnerability detailed in CVE-2026-96222. support.microsoft.com
  12. 12. This security update addresses a remote code execution vulnerability detailed in CVE-2026-96224. support.microsoft.com
  13. 13. This security update addresses a denial of service vulnerability detailed in CVE-2026-96233. support.microsoft.com
  14. 14. This security update addresses a denial of service vulnerability detailed in CVE-2026-96958. support.microsoft.com
  15. 15. This security update addresses a denial of service vulnerability detailed in CVE-2026-96959. support.microsoft.com
  16. 16. This security update addresses a denial of service vulnerability detailed in CVE-2026-96960. support.microsoft.com
  17. 17. This security update addresses an information disclosure vulnerability detailed in CVE-2026-97788. support.microsoft.com
  18. 18. This security update addresses a tampering vulnerability detailed in CVE-2026-97801. support.microsoft.com
  19. 19. This security update addresses a security feature bypass vulnerability detailed in CVE-2026-108398. support.microsoft.com
Checked automatically: 7 of 8 checks passed, 19 quoted passages · compared with Microsoft's page on Nov 14, 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 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