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KB5120702: Overview with user sentiment and feedback

Last Updated September 4, 2026

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Known Issues

Overview

KB5120702 is a cumulative security and reliability update for .NET Framework 4.8 released on August 11, 2026, targeting Windows 10 version 1607 and Windows Server 2016. This patch addresses six security vulnerabilities including multiple remote code execution and elevation of privilege issues. Microsoft recommends applying this update as part of regular maintenance routines, though users should be aware of reported compatibility issues with certain WPF applications.

General Purpose

  • Addresses six critical security vulnerabilities: two elevation of privilege issues (CVE-2026-65810, CVE-2026-62872), three remote code execution vulnerabilities (CVE-2026-62886, CVE-2026-62897, CVE-2026-70354), and one information disclosure vulnerability (CVE-2026-62902)
  • Provides cumulative reliability improvements to .NET Framework 4.8
  • Requires .NET Framework 4.8 to be pre-installed before applying
  • Available through Windows Update, Microsoft Update, WSUS, and the Microsoft Update Catalog

General Sentiment

The patch addresses significant security concerns with multiple critical vulnerabilities, which is essential for system protection. However, the update introduces two confirmed compatibility issues affecting WPF applications that handle printing and PDF/XPS content generation. Microsoft has provided workarounds for both issues but notes these are temporary measures that may reduce security protections. The patch is still under investigation status, indicating ongoing monitoring for additional issues.

Known Issues

  • WPF applications may fail with System.IO.FileFormatException when printing or generating PDF/XPS content using certain fonts including Calibri (Status: Investigating)
  • WPF applications printing or displaying print preview from in-memory XPS documents registered with System.IO.Packaging.PackageStore may fail with System.IO.FileFormatException when using absolute URIs with pack scheme (Status: Investigating)

Disclaimer: We take measures to ensure that AI-generated content is of the highest possible quality, but we cannot guarantee its accuracy and recommend that users do their own independent research. Generated on 2026-09-04 01:07 PM

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