CVE-2026-109481

## Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components. The Blazor/SignalR `/_blazor/refresh` path can accept a cross-site request that binds a victim's authenticated principal to an attacker-owned circuit. ## Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/506 ## CVSS Details - **Version:** 3.1 - **Severity:** High - **Score:** 7.5 (base score) - **Vector:** `CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C` - **Weakness:** CWE-352 ## Affected Platforms - **Platforms:** Windows, Linux, macOS - **Architectures:** All ## <a name="affected-packages"></a>Affected Packages The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately. ### .NET 11.0 - affected runtime packages Package | Affected version | Patched version --- | --- | --- [Microsoft.AspNetCore.App.Runtime.linux-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm) | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 [Microsoft.AspNetCore.App.Runtime.linux-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm64) | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 [Microsoft.AspNetCore.App.Runtime.linux-musl-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm) | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 [Microsoft.AspNetCore.App.Runtime.linux-musl-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm64) | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 [Microsoft.AspNetCore.App.Runtime.linux-musl-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-x64) | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148