CVE-2023-35391

ASP.NET Core SignalR and Visual Studio Information Disclosure Vulnerability

ASP.NET Core SignalR and Visual Studio Information Disclosure Vulnerability

Microsoft Security Advisory CVE-2023-35391: .NET Information Disclosure Vulnerability

<a name="executive-summary"></a>Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET core 2.1, .NET 6.0 and, .NET 7.0. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

A vulnerability exists in ASP.NET Core 2.1, .NET 6.0 and, .NET 7.0 applications using SignalR when redis backplane use might result in information disclosure.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/267

<a name="mitigation-factors"></a>Mitigation factors

Microsoft has not identified any mitigating factors for this vulnerability.

<a name="affected-software"></a>Affected software

• Any .NET 7.0 application running on .NET 7.0.9 or earlier.
• Any .NET 6.0 application running on .NET 6.0.20 or earlier.

If your application uses the following package versions, ensure you update to the latest version of .NET.

<a name=".NET 7"></a>.NET 7

Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.SignalR.StackExchangeRedis | >= 7.0.0, <= 7.0.9 | 7.0.10

<a name=".NET 6"></a>.NET 6

Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.SignalR.StackExchangeRedis | >= 6.0.0, <= 6.0.20 | 6.0.21

<a name="ASP.NET Core 2.1"></a>ASP.NET Core 2.1

Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.SignalR.Redis | < 1.0.40 | 1.0.40

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

If you have a runtime or SDK with a version listed, or an affected package listed in affected software, you're exposed to the vulnerability.

<a name="how-fix"></a>How do I fix the issue?

• To fix the issue please install the latest version of .NET 6.0 or .NET 7.0. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs.
• If you are using one of the affected packages, please update to the patched version listed above.
• If you have .NET 6.0 or greater installed, you can list the versions you have installed by running the dotnet --info command. You will see output like the following;

.NET Core SDK (reflecting any global.json):

 Version:   6.0.300
 Commit:    8473146e7d

Runtime Environment:

 OS Name:     Windows
 OS Version:  10.0.18363
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\6.0.300\

Host (useful for support):

  Version: 6.0.5
  Commit:  8473146e7d

.NET Core SDKs installed:

  6.0.300 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:

  Microsoft.AspNetCore.App 6.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 6.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 6.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

• If you're using .NET 7.0, you should download and install Runtime 7.0.10 or SDK 7.0.110 (for Visual Studio 2022 v17.4) from https://dotnet.microsoft.com/download/dotnet-core/7.0.
• If you're using .NET 6.0, you should download and install Runtime 6.0.21 or SDK 6.0.316 (for Visual Studio 2022 v17.2) from https://dotnet.microsoft.com/download/dotnet-core/6.0.

.NET 6.0 and and .NET 7.0…

ASP.NET Core SignalR and Visual Studio Information Disclosure Vulnerability

ASP.NET Core SignalR and Visual Studio Information Disclosure Vulnerability

ASP.NET Core SignalR and Visual Studio Information Disclosure Vulnerability