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Microsoft Security Response CenterCVE-2026-69439

.NET and Visual Studio Elevation of Privilege Vulnerability

HighVendor CVSS 8.8 / 10 1 CVE Published Sep 8, 2026 at 7:00 AM UTC
Get alerts for NET 10.0 runtime installed on Windows

Summary

Heap-based buffer overflow in .NET and Visual Studio allows an unauthorized attacker to elevate privileges over a network.

Products covered

  • .NET 10.0 runtime installed on Windows

  • .NET 8.0 runtime installed on Windows

  • .NET 9.0 runtime installed on Windows

  • Microsoft Visual Studio 2022 version 17.14

  • Microsoft Visual Studio 2026 version 18.9

  • .NET 11.0 runtime installed on Windows

Remediation

Release Notes Install KB5126106. Install KB5126104. Install KB5126105.

Vendor-listed fixes

  • 10.0.12

  • 8.0.31

  • 9.0.20

  • 17.14.40

  • 18.9.3

  • 11.0 RC1

CVEs in this advisory 1

CVE-2026-69439
Update history

What changed in later vendor updates

SecurityAlert records field-level changes from the point we begin following a bulletin. Earlier vendor changes may not have a field-by-field record.

    • Added affected products: .NET 8.0 runtime installed on Windows, .NET 9.0 runtime installed on Windows, .NET 10.0 runtime installed on Windows, .NET 11.0 runtime installed on Windows.
    • Removed affected products: .NET 8.0 installed on Windows, .NET 9.0 installed on Windows, .NET 10.0 installed on Windows, .NET 11.0 installed on Windows.
    • The vendor changed the advisory's last-updated date.

Updates

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Added to SecurityAlert

    We collected the advisory from the official source.

  3. Updated by Microsoft Security Response Center

    The vendor changed the advisory after it was first published.

  4. Confirmed at the source

    Our collector saw this advisory during a later source check.

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