- What: A security update addresses a vulnerability in .NET for Ubuntu 24.04 LTS related to improper handling of missing elements in the System.Security.Cryptography.Cose component.
- Impact: Attackers could bypass security checks and gain unauthorized access or perform data manipulation.
- Affected: .NET CLI tools and runtime on Ubuntu 24.04 LTS.
Ubuntu Security Notices USN-8025-2 USN-8025-2: .NET vulnerability Publication date 16 February 2026 Overview .NET could be made to bypass security features. Releases 24.04 LTS Packages dotnet10 - .NET CLI tools and runtime dotnet8 - .NET CLI tools and runtime Details USN 8025-1 fixed a vulnerability in .NET. This update provides the corresponding fix for Ubuntu 24.04 LTS. Original advisory details: Kevin Jones discovered that the System.Security.Cryptography.Cose component in .NET did not properly handle certain missing special elements in input data. An attacker could possibly use this issue to bypass security checks and gain unauthorized access or perform data manipulation. USN 8025-1 fixed a vulnerability in .NET. This update provides the corresponding fix for Ubuntu 24.04 LTS. Original advisory details: Kevin Jones discovered that the System.Security.Cryptography.Cose component in .NET did not properly handle certain missing special elements in input data. An attacker could possibly use this issue to bypass security checks and gain unauthorized access or perform data manipulation. 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 24.04 LTS noble aspnetcore-runtime-10.0 – 10.0.3-0ubuntu1~24.04.1 aspnetcore-runtime-8.0 – 8.0.24-0ubuntu1~24.04.1 dotnet-host-10.0 – 10.0.3-0ubuntu1~24.04.1 dotnet-host-8.0 – 8.0.24-0ubuntu1~24.04.1 dotnet-hostfxr-10.0 – 10.0.3-0ubuntu1~24.04.1 dotnet-hostfxr-8.0 – 8.0.24-0ubuntu1~24.04.1 dotnet-runtime-10.0 – 10.0.3-0ubuntu1~24.04.1 dotnet-runtime-8.0 – 8.0.24-0ubuntu1~24.04.1 dotnet-sdk-10.0 – 10.0.103-0ubuntu1~24.04.1 dotnet-sdk-8.0 – 8.0.124-0ubuntu1~24.04.1 dotnet-sdk-aot-10.0 – 10.0.103-0ubuntu1~24.04.1 dotnet10 – 10.0.103-10.0.3-0ubuntu1~24.04.1 dotnet8 – 8.0.124-8.0.24-0ubuntu1~24.04.1 Reduce your security exposure Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines. Get Ubuntu Pro References CVE-2026-21218 CVE-2026-21218 USN-8025-1 USN-8025-1