KB5120713: Overview with user sentiment and feedback
Last Updated September 30, 2026
Probability of successful installation and continued operation of the machine
Overview
Released on August 11, 2026, KB5120713 is a cumulative security and reliability update for .NET Framework 3.5 and 4.8.1 targeting Windows 11 version 23H2. This patch addresses six security vulnerabilities including elevation of privilege and remote code execution issues. The update is distributed through Windows Update, Microsoft Update, and WSUS channels.
General Purpose
- Addresses two elevation of privilege vulnerabilities (CVE-2026-65810, CVE-2026-62872) in .NET Framework
- Resolves three remote code execution vulnerabilities (CVE-2026-62886, CVE-2026-62897, CVE-2026-70354)
- Fixes an information disclosure vulnerability (CVE-2026-62902)
- Introduces enhanced font handling security protections for WPF applications
- Implements stricter XPS package boundary validation for improved application security
General Sentiment
The patch addresses critical security vulnerabilities and is recommended for regular maintenance deployment. However, the update introduces two confirmed compatibility issues affecting WPF applications that handle printing and PDF/XPS generation. Microsoft has provided workarounds for both issues but notes that one remains under investigation, suggesting organizations should test thoroughly before broad deployment, particularly if they rely on WPF-based applications for document processing.
Known Issues
- WPF applications may fail with System.IO.FileFormatException when printing or generating PDF/XPS content using certain fonts including Calibri (resolved in September 2026 update)
- WPF applications printing or displaying print preview from in-memory XPS documents registered with System.IO.Packaging.PackageStore may fail with System.IO.FileFormatException due to incorrect package boundary validation (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 2026-09-30 01:43 PM
