Description
Improper handling of missing special element in .NET allows an unauthorized attacker to perform spoofing over a network.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Microsoft | .NET 10.0 | 10.0.0 – < 10.0.3 | 10.0.3 |
| Microsoft | .NET 8.0 | 8.0.0 – < 8.0.24 | 8.0.24 |
| Microsoft | .NET 9.0 | 9.0.0 – < 9.0.13 | 9.0.13 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 25.10 | dotnet10 | 10.0.103-10.0.3-0ubuntu1~25.10.1 | USN-8025-1 |
| Ubuntu 25.10 | dotnet8 | 8.0.124-8.0.24-0ubuntu1~25.10.1 | USN-8025-1 |
| Ubuntu 25.10 | dotnet9 | 9.0.114-9.0.13-0ubuntu1~25.10.1 | USN-8025-1 |
| Ubuntu 24.04 LTS | dotnet10 | 10.0.103-10.0.3-0ubuntu1~24.04.1 | USN-8025-2 |
| Ubuntu 24.04 LTS | dotnet8 | 8.0.124-8.0.24-0ubuntu1~24.04.1 | USN-8025-2 |
| Ubuntu 22.04 LTS | dotnet6 +1 | No fix yet | — |
| Ubuntu 22.04 LTS | dotnet8 | 8.0.124-8.0.24-0ubuntu1~22.04.1 | USN-8025-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | dotnet10-runtime | 10.0.3-r0 | — |
| Alpine v3.24 | dotnet8-runtime | 8.0.24-r0 | — |
| Alpine v3.24 | dotnet9-runtime | 9.0.13-r0 | — |
| Alpine v3.23 | dotnet10-runtime | 10.0.3-r0 | — |
| Alpine v3.23 | dotnet8-runtime | 8.0.24-r0 | — |
| Alpine v3.23 | dotnet9-runtime | 9.0.13-r0 | — |
| Alpine v3.22 | dotnet8-runtime | 8.0.24-r0 | — |
| Alpine v3.22 | dotnet9-runtime | 9.0.13-r0 | — |
| Alpine v3.21 | dotnet8-runtime | 8.0.24-r0 | — |
| Alpine v3.21 | dotnet9-runtime | 9.0.13-r0 | — |
| Alpine v3.20 | dotnet8-runtime | 8.0.24-r0 | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | dotnet-10 | 10.0.103-r0 | — |
| Wolfi rolling | dotnet-8 | 8.0.124-r0 | — |
| Wolfi rolling | dotnet-9 | 9.0.114-r0 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| NuGet | System.Security.Cryptography.Cose | >= 8.0.0, < 8.0.2 | 8.0.2 | GHSA-qvhc-9v3j-5rfw |
| NuGet | System.Security.Cryptography.Cose | >= 9.0.0, < 9.0.13 | 9.0.13 | GHSA-qvhc-9v3j-5rfw |
| NuGet | System.Security.Cryptography.Cose | >= 10.0.0, < 10.0.3 | 10.0.3 | GHSA-qvhc-9v3j-5rfw |
Advisories 6
- VDE-2026-064 METTLER TOLEDO: LabX Standard Report on External Component Analysis - v21.3 CERT@VDE · Jun 9, 2026
- USN-8025-2 dotnet8, dotnet10 vulnerability Ubuntu Security Notices (USN) · Apr 27, 2026
- USN-8025-1 dotnet8, dotnet9, dotnet10 vulnerability Ubuntu Security Notices (USN) · Apr 27, 2026
- WID-SEC-2026-0367 Microsoft DeveloperTools (Visual Studio Code und .NET): Mehrere Schwachstellen BSI CERT-Bund (WID) · Apr 6, 2026
- NCSC-2026-0056 Kwetsbaarheden verholpen in Microsoft Developer Tools NCSC-NL (Netherlands) · Feb 10, 2026
- MSRC-CVE-2026-21218 .NET Spoofing Vulnerability Microsoft Security Response Center · Feb 10, 2026
References
- .NET Spoofing Vulnerability vendor-advisory patch