USN-8085-1: .NET vulnerabilities

Publication date

11 March 2026

Overview

Several security issues were fixed in .NET.


Packages

  • dotnet10 - .NET CLI tools and runtime
  • dotnet8 - .NET CLI tools and runtime
  • dotnet9 - .NET CLI tools and runtime

Details

It was discovered that the .NET Microsoft.Bcl.Memory NuGet package did not
properly handle certain malformed Base64Url encoded input. An attacker could
possibly use this issue to cause .NET to crash, resulting in a denial of
service. This issue only affected .NET 9.0 and .NET 10.0. (CVE-2026-26127)

Bartłomiej Dach discovered that .NET's SignalR server component did not
properly manage resource consumption when processing certain messages. An
attacker could possibly use this issue to exhaust internal buffers, resulting
in a denial of service. (CVE-2026-26130)

It was discovered that the .NET Microsoft.Bcl.Memory NuGet package did not
properly handle certain malformed Base64Url encoded input. An attacker could
possibly use this issue to cause .NET to crash, resulting in a denial of
service. This issue only affected .NET 9.0 and .NET 10.0. (CVE-2026-26127)

Bartłomiej Dach discovered that .NET's SignalR server component did not
properly manage resource consumption when processing certain messages. An
attacker could possibly use this issue to exhaust internal buffers, resulting
in a denial of service. (CVE-2026-26130)

Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
25.10 questing aspnetcore-runtime-10.0 –  10.0.4-0ubuntu1~25.10.1
aspnetcore-runtime-8.0 –  8.0.25-0ubuntu1~25.10.1
aspnetcore-runtime-9.0 –  9.0.14-0ubuntu1~25.10.1
dotnet-host-10.0 –  10.0.4-0ubuntu1~25.10.1
dotnet-host-8.0 –  8.0.25-0ubuntu1~25.10.1
dotnet-host-9.0 –  9.0.14-0ubuntu1~25.10.1
dotnet-hostfxr-10.0 –  10.0.4-0ubuntu1~25.10.1
dotnet-hostfxr-8.0 –  8.0.25-0ubuntu1~25.10.1
dotnet-hostfxr-9.0 –  9.0.14-0ubuntu1~25.10.1
dotnet-runtime-10.0 –  10.0.4-0ubuntu1~25.10.1
dotnet-runtime-8.0 –  8.0.25-0ubuntu1~25.10.1
dotnet-runtime-9.0 –  9.0.14-0ubuntu1~25.10.1
dotnet-sdk-10.0 –  10.0.104-0ubuntu1~25.10.1
dotnet-sdk-8.0 –  8.0.125-0ubuntu1~25.10.1
dotnet-sdk-9.0 –  9.0.115-0ubuntu1~25.10.1
dotnet-sdk-aot-10.0 –  10.0.104-0ubuntu1~25.10.1
dotnet-sdk-aot-9.0 –  9.0.115-0ubuntu1~25.10.1
dotnet10 –  10.0.104-10.0.4-0ubuntu1~25.10.1
dotnet8 –  8.0.125-8.0.25-0ubuntu1~25.10.1
dotnet9 –  9.0.115-9.0.14-0ubuntu1~25.10.1
24.04 LTS noble aspnetcore-runtime-10.0 –  10.0.4-0ubuntu1~24.04.1
aspnetcore-runtime-8.0 –  8.0.25-0ubuntu1~24.04.1
dotnet-host-10.0 –  10.0.4-0ubuntu1~24.04.1
dotnet-host-8.0 –  8.0.25-0ubuntu1~24.04.1
dotnet-hostfxr-10.0 –  10.0.4-0ubuntu1~24.04.1
dotnet-hostfxr-8.0 –  8.0.25-0ubuntu1~24.04.1
dotnet-runtime-10.0 –  10.0.4-0ubuntu1~24.04.1
dotnet-runtime-8.0 –  8.0.25-0ubuntu1~24.04.1
dotnet-sdk-10.0 –  10.0.104-0ubuntu1~24.04.1
dotnet-sdk-8.0 –  8.0.125-0ubuntu1~24.04.1
dotnet-sdk-aot-10.0 –  10.0.104-0ubuntu1~24.04.1
dotnet10 –  10.0.104-10.0.4-0ubuntu1~24.04.1
dotnet8 –  8.0.125-8.0.25-0ubuntu1~24.04.1
22.04 LTS jammy aspnetcore-runtime-8.0 –  8.0.25-0ubuntu1~22.04.1
dotnet-host-8.0 –  8.0.25-0ubuntu1~22.04.1
dotnet-hostfxr-8.0 –  8.0.25-0ubuntu1~22.04.1
dotnet-runtime-8.0 –  8.0.25-0ubuntu1~22.04.1
dotnet-sdk-8.0 –  8.0.125-0ubuntu1~22.04.1
dotnet8 –  8.0.125-8.0.25-0ubuntu1~22.04.1

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