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September 8, 2026, KB5126043 Cumulative Update for .NET Framework 3.5 and 4.7.2
Checked 28 Sep 2026. BlackTree preserves the last verified facts if a later source check is temporarily unavailable.
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CUMULATIVE UPDATEMICROSOFTVERIFIED
PUBLISHER UPDATE · KB5126043
KB5126043 release notes and known issues
September 8, 2026, KB5126043 Cumulative Update for .NET Framework 3.5 and 4.7.2
Scope: .NET Framework. This update record adds version, fix and known-issue context. Its publication date is not a lifecycle boundary.
Summary
Microsoft's September 2026 cumulative update for .NET Framework 3.5 and 4.7.2 on Windows 10 version 1809 and Windows Server 2019.
Improvements and security content
- Addresses CVE-2026-62886.
- Addresses CVE-2026-69522.
Known issues
Publisher statementNo known issues reported. Microsoft states that it is not currently aware of any issues in this update.
Affected products and versions
Products
- .NET Framework 3.5
- .NET Framework 4.7.2
- Windows 10 version 1809
- Windows Server 2019
Affected versions
- .NET Framework 3.5
- .NET Framework 4.7.2
Fixed versions or updates
- KB5126043
Recommended action
Apply the update through a supported Microsoft servicing channel after normal deployment validation.