USN-7822-1: .NET vulnerabilities

Publication date

16 October 2025

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 .NET did not properly handle the creation of temporary
build time directories. An attacker could possibly use this issue to cause a
denial of service. (CVE-2025-55247)

It was discovered that .NET did not properly establish TLS sessions for
SMTP server connections. An attacker could use this issue to cause .NET
to use unencrypted connections. This issue only affects .NET versions 8.0
and 9.0. (CVE-2025-55248)

It was discovered that .NET inconsistently interpreted certain http
requests. An attacker could possibly use this to bypass a security feature
over a network. (CVE-2025-55315)

It was discovered that .NET did not properly handle the creation of temporary
build time directories. An attacker could possibly use this issue to cause a
denial of service. (CVE-2025-55247)

It was discovered that .NET did not properly establish TLS sessions for
SMTP server connections. An attacker could use this issue to cause .NET
to use unencrypted connections. This issue only affects .NET versions 8.0
and 9.0. (CVE-2025-55248)

It was discovered that .NET inconsistently interpreted certain http
requests. An attacker could possibly use this to bypass a security feature
over a network. (CVE-2025-55315)

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 –  10.0.0~rc2-0ubuntu1~25.10.2
aspnetcore-runtime-8.0 –  8.0.21-0ubuntu1~25.10.1
aspnetcore-runtime-9.0 –  9.0.10-0ubuntu1~25.10.1
dotnet-host-10.0 –  10.0.0~rc2-0ubuntu1~25.10.2
dotnet-host-8.0 –  8.0.21-0ubuntu1~25.10.1
dotnet-host-9.0 –  9.0.10-0ubuntu1~25.10.1
dotnet-hostfxr-10.0 –  10.0.0~rc2-0ubuntu1~25.10.2
dotnet-hostfxr-8.0 –  8.0.21-0ubuntu1~25.10.1
dotnet-hostfxr-9.0 –  9.0.10-0ubuntu1~25.10.1
dotnet-runtime-10.0 –  10.0.0~rc2-0ubuntu1~25.10.2
dotnet-runtime-8.0 –  8.0.21-0ubuntu1~25.10.1
dotnet-runtime-9.0 –  9.0.10-0ubuntu1~25.10.1
dotnet-sdk-10.0 –  10.0.100~rc2-0ubuntu1~25.10.2
dotnet-sdk-8.0 –  8.0.121-0ubuntu1~25.10.1
dotnet-sdk-9.0 –  9.0.111-0ubuntu1~25.10.1
dotnet-sdk-aot-10.0 –  10.0.100~rc2-0ubuntu1~25.10.2
dotnet-sdk-aot-9.0 –  9.0.111-0ubuntu1~25.10.1
dotnet10 –  10.0.100-10.0.0~rc2-0ubuntu1~25.10.2
dotnet8 –  8.0.121-8.0.21-0ubuntu1~25.10.1
dotnet9 –  9.0.111-9.0.10-0ubuntu1~25.10.1
25.04 plucky aspnetcore-runtime-8.0 –  8.0.21-0ubuntu1~25.04.1
aspnetcore-runtime-9.0 –  9.0.10-0ubuntu1~25.04.1
dotnet-host-8.0 –  8.0.21-0ubuntu1~25.04.1
dotnet-host-9.0 –  9.0.10-0ubuntu1~25.04.1
dotnet-hostfxr-8.0 –  8.0.21-0ubuntu1~25.04.1
dotnet-hostfxr-9.0 –  9.0.10-0ubuntu1~25.04.1
dotnet-runtime-8.0 –  8.0.21-0ubuntu1~25.04.1
dotnet-runtime-9.0 –  9.0.10-0ubuntu1~25.04.1
dotnet-sdk-8.0 –  8.0.121-0ubuntu1~25.04.1
dotnet-sdk-9.0 –  9.0.111-0ubuntu1~25.04.1
dotnet-sdk-aot-9.0 –  9.0.111-0ubuntu1~25.04.1
dotnet8 –  8.0.121-8.0.21-0ubuntu1~25.04.1
dotnet9 –  9.0.111-9.0.10-0ubuntu1~25.04.1
24.04 LTS noble aspnetcore-runtime-8.0 –  8.0.21-0ubuntu1~24.04.1
dotnet-host-8.0 –  8.0.21-0ubuntu1~24.04.1
dotnet-hostfxr-8.0 –  8.0.21-0ubuntu1~24.04.1
dotnet-runtime-8.0 –  8.0.21-0ubuntu1~24.04.1
dotnet-sdk-8.0 –  8.0.121-0ubuntu1~24.04.1
dotnet8 –  8.0.121-8.0.21-0ubuntu1~24.04.1
22.04 LTS jammy aspnetcore-runtime-8.0 –  8.0.21-0ubuntu1~22.04.1
dotnet-host-8.0 –  8.0.21-0ubuntu1~22.04.1
dotnet-hostfxr-8.0 –  8.0.21-0ubuntu1~22.04.1
dotnet-runtime-8.0 –  8.0.21-0ubuntu1~22.04.1
dotnet-sdk-8.0 –  8.0.121-0ubuntu1~22.04.1
dotnet8 –  8.0.121-8.0.21-0ubuntu1~22.04.1

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