Executive brief
A security vulnerability has been identified in the .NET HTTP client, a component used by developers to enable applications to communicate over the internet. An attacker can exploit this flaw to crash an application by forcing it to run out of memory. This could lead to service outages and impact the availability of business-critical applications built on .NET.
Technical details
A denial of service vulnerability (CWE-770) exists in the .NET HTTP client (System.Net.Http) due to improper resource allocation limits when handling HTTP/2 traffic. A remote, unauthenticated attacker can exploit this by sending specially crafted HTTP/2 requests that trigger an out-of-memory (OOM) condition in the application process. The vulnerability affects .NET 8, 9, and 10 across all platforms and architectures. Exploitation does not require user interaction or special privileges. Microsoft has released patches in .NET versions 8.0.29, 9.0.18, and 10.0.10. Developers must update their runtimes and recompile any self-contained applications.
Affected products
- Microsoft .NET Runtime 8.0.0 - 8.0.28, 9.0.0 - 9.0.17, 10.0.0 - 10.0.9
Timeline
- 2026-07-14: disclosed: Advisory published by Microsoft
- 2026-07-14: patched: Patched versions released for .NET 8, 9, and 10
References
- https://github.com/dotnet/runtime/security/advisories/GHSA-wp74-jgxh-gv4q
- https://github.com/dotnet/announcements/issues/422
- https://github.com/dotnet/runtime/issues/130715
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50651
- https://api.github.com/repos/dotnet/runtime/security-advisories/GHSA-wp74-jgxh-gv4q