CVE-2026-96230

## Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.Components.WebAssembly.Server. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. The Blazor WebAssembly development-server debug page can reflect unencoded exception text, allowing cross-origin script injection through the unauthenticated `/_framework/debug` endpoint used by `dotnet watch`. ## Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/478 ## 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-79 (Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) ## Affected Platforms - **Platforms:** Windows, Linux, macOS - **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.AspNetCore.Components.WebAssembly.Server](https://www.nuget.org/packages/Microsoft.AspNetCore.Components.WebAssembly.Server) | >= 10.0.0, <= 10.0.12 | 10.0.13 [Microsoft.AspNetCore.Components.WebAssembly.Server](https://www.nuget.org/packages/Microsoft.AspNetCore.Components.WebAssembly.Server) | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 [Microsoft.AspNetCore.Components.WebAssembly.Server](https://www.nuget.org/packages/Microsoft.AspNetCore.Components.WebAssembly.Server) | >= 8.0.0, <= 8.0.31 | 8.0.32 [Microsoft.AspNetCore.Components.WebAssembly.Server](https://www.nuget.org/packages/Microsoft.AspNetCore.Components.WebAssembly.Server) | >= 9.0.0, <= 9.0.20 | 9.0.21 ## Advisory FAQ ### <a name="how-affected"></a>How do I know if I am affected? If using a package l