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

KB5082427

KB5082427: Cumulative update for .NET Framework, versions 3.5 and 4.8, on Windows Server 2022, April 2026. Critical service-disruption flaw addressed; ClickOnce checks expanded

In short

Six .NET Framework vulnerabilities are addressed, including one critical flaw that can cause denial of service. ClickOnce checks now support SHA384 and SHA512.

Does it affect you? Applies to: Windows Server 2022 systems with .NET Framework 3.5 or 4.8 installed.

File version
2.0.50727.9181 · 4.8.4801.0
Security
6 fixed · 1 critical
Restart
Required

What changes

Fixes 6 changes

.NET Framework

6 items

For: Windows Server 2022 systems

  • A flaw that could let code run remotely is addressed.1
    CVE-2026-32178: remote code execution vulnerability.
  • A flaw that could disrupt a service is addressed.2
    CVE-2026-32203: denial-of-service vulnerability.
  • A flaw that could disrupt a service is addressed.3
    CVE-2026-32226: denial-of-service vulnerability.
  • A critical flaw that could disrupt a service is addressed.4
    CVE-2026-23666: denial-of-service vulnerability.
  • A flaw that could bypass a security feature is addressed.5
    CVE-2026-26171: security feature bypass vulnerability.
  • A flaw that could expose information is addressed.6
    CVE-2026-33116: information disclosure vulnerability.

Improvement 1 change

.NET Runtime

For: Applications that use ClickOnce

  • ClickOnce checks now support SHA384 and SHA512.7
    Adds verification logic for ClickOnce to support SHA384 and SHA512.

Technical details

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

Data sheet

Released
2026-04-14
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5066139, KB5065748
Replaced by
KB5087068
VersionFile versionChannel
3.5 2.0.50727.9181 General availability
4.8 4.8.4801.0 General availability

Security

6 vulnerabilities fixed
1 critical 2 important 3 not rated
VulnerabilitySeverityCVSS
CVE-2026-23666
.NET Framework Denial of Service Vulnerability
 Critical 7.5
CVE-2026-33116
.NET, .NET Framework, and Visual Studio Denial of Service Vulnerability
 Important 7.5
CVE-2026-32226
.NET Framework Denial of Service Vulnerability
 Important 5.9
CVE-2026-26171
.NET Denial of Service Vulnerability
 Not rated —
CVE-2026-32178
.NET Spoofing Vulnerability
 Not rated —
CVE-2026-32203
.NET and Visual Studio Denial of Service Vulnerability
 Not rated —

Downloads (Microsoft Update Catalog)

x64 Windows Server 2022
74.6 MB
windows10.0-kb5082427-x64-ndp48.msu Main update · KB5082427 SHA-1: 93c2fe73…77d82f

Updated components

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

Top changed componentsFiles
WCF14
Windows Forms2

Sources

Updated
Cited passages from Microsoft's official notes (7)
  1. 1. This security update addresses a remote code execution vulnerability detailed in CVE-2026-32178. support.microsoft.com
  2. 2. This security update addresses a denial-of-service vulnerability detailed in CVE-2026-32203. support.microsoft.com
  3. 3. This security update addresses a denial-of-service vulnerability detailed in CVE-2026-32226. support.microsoft.com
  4. 4. This security update addresses a denial-of-service vulnerability detailed in CVE-2026-23666. support.microsoft.com
  5. 5. This security update addresses a security feature bypass vulnerability detailed in CVE-2026-26171. support.microsoft.com
  6. 6. This security update addresses an information disclosure vulnerability detailed in CVE-2026-33116. support.microsoft.com
  7. 7. Addresses an issue to add verification logic for ClickOnce to support SHA384 and SHA512 support.microsoft.com
Checked automatically: 7 of 8 checks passed, 7 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