Out-of-bounds write in .NET Framework allows an unauthorized attacker to execute code over a network.

Affected: NuGet: Microsoft.WindowsDesktop.App.Runtime.win-arm64, NuGet: Microsoft.WindowsDesktop.App.Runtime.win-x64, NuGet: Microsoft.WindowsDesktop.App.Runtime.win-x86

## Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.WindowsDesktop.App.Runtime (WPF). This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

Crafted WPF pixel-shader bytecode can desynchronize the two parsing passes in `CPSTrans::Initialize`, causing heap out-of-bounds writes or reads.

## Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/450

## CVSS Details

- **Version:** 3.1 - **Severity:** High - **Score:** 8.8 - **Vector:** `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`

- **Weakness:** CWE-787 (Out-of-bounds Write) ## Affected Platforms

- **Platforms:** Windows - **Architectures:** All

## <a name="affected-packages"></a>Affected Packages

The vulnerability affects Microsoft .NET projects that use an affected package version listed below.

Package name | Affected version | Patched version ------------ | ---------------- | --------------- [Microsoft.WindowsDesktop.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-arm64) | >= 9.0.0, <= 9.0.20 | 9.0.21 [Microsoft.WindowsDesktop.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x64) | >= 9.0.0, <= 9.0.20 | 9.0.21 [Microsoft.WindowsDesktop.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x86) | >= 9…