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.NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 Security update
Patch Tuesday

KB5087064

KB5087064: Cumulative update for .NET Framework, versions 3.5 and 4.8, on Windows 10 21H2/22H2, May 2026. Two runtime privilege flaws addressed

In short

The update addresses two .NET Framework flaws that could let an attacker gain higher access. It applies to Windows 10 versions 21H2 and 22H2.

Does it affect you? Applies to: Devices running Windows 10 version 21H2 or 22H2 with .NET Framework 3.5 or 4.8 installed.

File version
2.0.50727.9181 · 4.8.4802.0
Security
2 fixed
Restart
Required

What changes

Fixes 2 changes

.NET Framework

2 items
  • A flaw that could let an attacker gain higher access is addressed.1
    CVE-2026-32177 is an Elevation of Privilege vulnerability.
  • A second flaw that could let an attacker gain higher access is addressed.2
    CVE-2026-35433 is an Elevation of Privilege vulnerability.

Technical details

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

Data sheet

Released
2026-05-12
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5082426, KB5066135
Replaced by
KB5101006
VersionFile versionChannel
3.5 2.0.50727.9181 General availability
4.8 4.8.4802.0 General availability

Security

2 vulnerabilities fixed
2 important
VulnerabilitySeverityCVSS
CVE-2026-32177
.NET Elevation of Privilege Vulnerability
 Important 7.3
CVE-2026-35433
.NET Elevation of Privilege Vulnerability
 Important 7.3

Downloads (Microsoft Update Catalog)

x64 Windows 10 Enterprise LTSC 2021 / Windows 10, version 22H2
76.4 MB
windows10.0-kb5087064-x64-ndp48.msu Main update · KB5087064 SHA-1: 55417013…dfb4cd
Arm64 Windows 10 Enterprise LTSC 2021 / Windows 10, version 22H2
47.7 MB
windows10.0-kb5087064-arm64-ndp48.msu Main update · KB5087064 SHA-1: ded24fa2…ba071c
x86 Windows 10 Enterprise LTSC 2021 / Windows 10, version 22H2
47.7 MB
windows10.0-kb5087064-x86-ndp48.msu Main update · KB5087064 SHA-1: 1635d241…f1d2c4

Updated components

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

Top changed componentsFiles
WPF42

Sources

Updated
Cited passages from Microsoft's official notes (2)
  1. 1. This security update addresses a Elevation of Privilege vulnerability detailed in CVE-2026-32177. support.microsoft.com
  2. 2. This security update addresses a Elevation of Privilege vulnerability detailed in CVE-2026-35433. support.microsoft.com
Checked automatically: 8 of 8 checks passed, 2 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: 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