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Microsoft WindowsDesktop.App.Runtime contains a critical security vulnerability within Windows Presentation Foundation (WPF) pixel-shader bytecode parsing. Specifically, when an application processes a maliciously crafted WPF pixel-shader file, a dangerous flaw occurs during the initialization phase inside CPSTrans::Initialize. The parser fails to properly synchronize its two separate evaluation and parsing passes over the input data. This profound synchronization mismatch allows an attacker to manipulate internal buffer sizing and structural offsets, directly causing severe heap out-of-bounds reads or out-of-bounds writes. Because heap memory structures can be corrupted or read arbitrarily, an attacker can leverage this condition to achieve remote code execution in the context of the user running the vulnerable desktop application, often triggered simply by enticing a user to open a file or view content containing the malformed shader instructions.
DailyCVE Form:
Platform: Windows
Version: .NET 8, 9, 10
Vulnerability : Remote Code Execution
Severity: High
date: 10/13/2026
Prediction: Patch Tuesday Released
What Undercode Say:
To verify the installed .NET runtime versions and ensure your environment is not exposing vulnerable package versions, you can execute the following command in your terminal:
dotnet --info
If your project references outdated packages like Microsoft.WindowsDesktop.App.Runtime, check your project file or package configuration and update the runtime references using:
dotnet add package Microsoft.WindowsDesktop.App.Runtime --version 10.0.13
Exploit: (Educational Purposes!)
The exploit vector relies on delivering malformed or crafted WPF pixel-shader bytecode to a target application utilizing the vulnerable WPF runtime libraries. During rendering or shader compilation, `CPSTrans::Initialize` evaluates the shader instructions. Due to the desynchronization between passes, bounds checking checks are bypassed, leading to heap corruption. In a lab environment, researchers construct a custom XAML or compiled shader resource containing invalid token lengths that trigger the heap out-of-bounds write, allowing instruction pointer redirection or memory disclosure when handled by the unpatched runtime.
Protection: from this CVE
To secure your applications against this vulnerability, immediately update your .NET SDK and runtime environments to the latest patched versions (such as version 10.0.13, 9.0.21, 8.0.32, or 11.0.0-rc.2 depending on your branch). Developers using Visual Studio should apply the latest IDE updates, which automatically bundle the secured .NET runtimes. For self-contained deployments, ensure that you fully recompile and redeploy your applications with the updated libraries included.
Impact:
Successful exploitation of this vulnerability grants an attacker the ability to execute arbitrary code with the privileges of the logged-on user. This can lead to total confidentiality, integrity, and availability compromise of the affected client machine, potentially allowing attackers to install programs, view, change, or delete data, or create new accounts with full user rights.
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Sources:
Reported By: github.com
Extra Source Hub:
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