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

KB5087054

KB5087054: Cumulative update for .NET Framework, versions 3.5 and 4.8.1, on Windows 11 24H2, May 2026. Two .NET privilege flaws addressed

In short

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

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

File version
2.0.50727.9181 · 4.8.9334.0
Security
2 fixed
Restart
Required

What changes

Improvements 2 changes

.NET Framework

2 items
  • A security flaw could let someone gain higher access than intended.1
    Addresses CVE-2026-32177, a .NET Framework Elevation of Privilege vulnerability.
  • A security flaw could let someone gain higher access than intended.2
    Addresses CVE-2026-35433, a .NET Framework 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
KB5082420, KB5074831, KB5066131, KB5064401
+7 earlier KB5056579, KB5054979, KB5050577, KB5049622, KB5048162, KB5045934, KB5044030
Replaced by
KB5101001
VersionFile versionChannel
3.5 2.0.50727.9181 General availability
4.8.1 4.8.9334.0 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

Updated components

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

Top changed componentsFiles
WPF28

Sources

Updated
Cited passages from Microsoft's official notes (2)
  1. 1. CVE-2026-32177 - .NET Framework Elevation of Privilege vulnerability support.microsoft.com
  2. 2. CVE-2026-35433 - .NET Framework Elevation of Privilege vulnerability support.microsoft.com
Checked automatically: 7 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: not passed

A second AI read the text against the sources: correctness 4/5, 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