Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 5.0, .NET Core 3.1 and .NET Core 2.1. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

An information disclosure vulnerability exists in .NET 5.0, .NET Core 3.1 and .NET Core 2.1 when dumps created by the tool to collect crash dumps and dumps on demand are created with global read permissions on Linux and macOS.

Patches

• If you're using .NET 5.0, you should download and install Runtime 5.0.9 or SDK 5.0.206 (for Visual Studio 2019 v16.8) or SDK 5.0.303 (for Visual Studio 2019 V16.10) from https://dotnet.microsoft.com/download/dotnet-core/5.0.

• If you're using .NET Core 3.1, you should download and install Runtime 3.1.18 or SDK 3.1.118 (for Visual Studio 2019 v16.4) or 3.1.412 (for Visual Studio 2019 v16.7 or later) from https://dotnet.microsoft.com/download/dotnet-core/3.1.

• If you're using .NET Core 2.1, you should download and install Runtime 2.1.29 or SDK 2.1.525 (for Visual Studio 2019 v15.9) or 2.1.817 from https://dotnet.microsoft.com/download/dotnet-core/2.1.

Other Details

• Announcement for this issue can be found at dotnet/announcements#196
• An Issue for this can be found at #57174
• MSRC details for this can be found at https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2021-34485