==========================================================================
Ubuntu Security Notice USN-8176-1
April 15, 2026

dotnet8, dotnet9, dotnet10 vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 25.10
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS

Summary:

Several security issues were fixed in .NET.

Software Description:
- dotnet10: .NET CLI tools and runtime
- dotnet8: .NET CLI tools and runtime
- dotnet9: .NET CLI tools and runtime

Details:

Ludvig Pedersen discovered that the System.Security.Cryptography.Xml
library in .NET incorrectly handled certain XML inputs. An attacker could
possibly use this issue to consume excessive resources, resulting in a
denial of service. (CVE-2026-33116, CVE-2026-26171)

Ludvig Pedersen and Kevin Jones discovered that the
System.Security.Cryptography.Xml library in .NET incorrectly handled
certain XML inputs. An attacker could possibly use this issue to cause
.NET to crash, resulting in a denial of service. (CVE-2026-32203)

Ludvig Pedersen discovered that the System.Net.Mail component in .NET
incorrectly handled certain inputs. An attacker could possibly use this
issue to perform a network spoofing attack. (CVE-2026-32178)

Update instructions:

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

Ubuntu 25.10
  aspnetcore-runtime-10.0         10.0.6-0ubuntu1~25.10.1
  aspnetcore-runtime-8.0          8.0.26-0ubuntu1~25.10.1
  aspnetcore-runtime-9.0          9.0.15-0ubuntu1~25.10.1
  dotnet-host-10.0                10.0.6-0ubuntu1~25.10.1
  dotnet-host-8.0                 8.0.26-0ubuntu1~25.10.1
  dotnet-host-9.0                 9.0.15-0ubuntu1~25.10.1
  dotnet-hostfxr-10.0             10.0.6-0ubuntu1~25.10.1
  dotnet-hostfxr-8.0              8.0.26-0ubuntu1~25.10.1
  dotnet-hostfxr-9.0              9.0.15-0ubuntu1~25.10.1
  dotnet-runtime-10.0             10.0.6-0ubuntu1~25.10.1
  dotnet-runtime-8.0              8.0.26-0ubuntu1~25.10.1
  dotnet-runtime-9.0              9.0.15-0ubuntu1~25.10.1
  dotnet-sdk-10.0                 10.0.106-0ubuntu1~25.10.1
  dotnet-sdk-8.0                  8.0.126-0ubuntu1~25.10.1
  dotnet-sdk-9.0                  9.0.116-0ubuntu1~25.10.1
  dotnet-sdk-aot-10.0             10.0.106-0ubuntu1~25.10.1
  dotnet-sdk-aot-9.0              9.0.116-0ubuntu1~25.10.1
  dotnet10                        10.0.106-10.0.6-0ubuntu1~25.10.1
  dotnet8                         8.0.126-8.0.26-0ubuntu1~25.10.1
  dotnet9                         9.0.116-9.0.15-0ubuntu1~25.10.1

Ubuntu 24.04 LTS
  aspnetcore-runtime-10.0         10.0.6-0ubuntu1~24.04.1
  aspnetcore-runtime-8.0          8.0.26-0ubuntu1~24.04.1
  dotnet-host-10.0                10.0.6-0ubuntu1~24.04.1
  dotnet-host-8.0                 8.0.26-0ubuntu1~24.04.1
  dotnet-hostfxr-10.0             10.0.6-0ubuntu1~24.04.1
  dotnet-hostfxr-8.0              8.0.26-0ubuntu1~24.04.1
  dotnet-runtime-10.0             10.0.6-0ubuntu1~24.04.1
  dotnet-runtime-8.0              8.0.26-0ubuntu1~24.04.1
  dotnet-sdk-10.0                 10.0.106-0ubuntu1~24.04.1
  dotnet-sdk-8.0                  8.0.126-0ubuntu1~24.04.1
  dotnet-sdk-aot-10.0             10.0.106-0ubuntu1~24.04.1
  dotnet10                        10.0.106-10.0.6-0ubuntu1~24.04.1
  dotnet8                         8.0.126-8.0.26-0ubuntu1~24.04.1

Ubuntu 22.04 LTS
  aspnetcore-runtime-8.0          8.0.26-0ubuntu1~22.04.1
  dotnet-host-8.0                 8.0.26-0ubuntu1~22.04.1
  dotnet-hostfxr-8.0              8.0.26-0ubuntu1~22.04.1
  dotnet-runtime-8.0              8.0.26-0ubuntu1~22.04.1
  dotnet-sdk-8.0                  8.0.126-0ubuntu1~22.04.1
  dotnet8                         8.0.126-8.0.26-0ubuntu1~22.04.1

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

References:
  https://ubuntu.com/security/notices/USN-8176-1
  CVE-2026-26171, CVE-2026-32178, CVE-2026-32203, CVE-2026-33116

Package Information:
  https://launchpad.net/ubuntu/+source/dotnet10/10.0.106-10.0.6-0ubuntu1~25.10.1
  https://launchpad.net/ubuntu/+source/dotnet8/8.0.126-8.0.26-0ubuntu1~25.10.1
  https://launchpad.net/ubuntu/+source/dotnet9/9.0.116-9.0.15-0ubuntu1~25.10.1
  https://launchpad.net/ubuntu/+source/dotnet10/10.0.106-10.0.6-0ubuntu1~24.04.1
  https://launchpad.net/ubuntu/+source/dotnet8/8.0.126-8.0.26-0ubuntu1~24.04.1
  https://launchpad.net/ubuntu/+source/dotnet8/8.0.126-8.0.26-0ubuntu1~22.04.1