GHSA-3m2r-q8x3-xmf7 — Microsoft.AspNetCore.Serv…
GHSA-3m2r-q8x3-xmf7 is a security vulnerability in Microsoft.AspNetCore.Server.Kestrel.Core. A fix is available for Microsoft.AspNetCore.Server.Kestrel.Core — see the affected versions and patch details below.
Moderate severity vulnerability that affects Microsoft.AspNetCore.All, Microsoft.AspNetCore.Server.Kestrel.Core, Microsoft.AspNetCore.Server.Kestrel.Transport.Abstractions, and Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv
Real-World Exposure
Microsoft.AspNetCore.Server.Kestrel.Core.NETMicrosoft.AspNetCore.Server.Kestrel.Transport.Abstractions.NETMicrosoft.AspNetCore.Server.Kestrel.Transport.Libuv.NETMicrosoft.AspNetCore.AllReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Microsoft made an internal discovery of a security vulnerability in version 2.x of ASP.NET Core where a specially crafted request can cause excess resource consumption in Kestrel.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.AspNetCore.Server.Kestrel.Core | ≥ 2.0.0&&< 2.0.3 | 2.0.3dotnet add package Microsoft.AspNetCore.Server.Kestrel.Core --version 2.0.3 |
| .NETNuGet | Microsoft.AspNetCore.Server.Kestrel.Transport.Abstractions | ≥ 2.0.0&&< 2.0.3 | 2.0.3dotnet add package Microsoft.AspNetCore.Server.Kestrel.Transport.Abstractions --version 2.0.3 |
| .NETNuGet | Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv | ≥ 2.0.0&&< 2.0.3 | 2.0.3dotnet add package Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv --version 2.0.3 |
| .NETNuGet | Microsoft.AspNetCore.All | ≥ 2.0.0&&< 2.0.8 | 2.0.8dotnet add package Microsoft.AspNetCore.All --version 2.0.8 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.AspNetCore.Server.Kestrel.Core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Microsoft.AspNetCore.Server.Kestrel.Core to 2.0.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3m2r-q8x3-xmf7 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-3m2r-q8x3-xmf7 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-3m2r-q8x3-xmf7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-3m2r-q8x3-xmf7 in your dependencies?
O3 Security finds GHSA-3m2r-q8x3-xmf7 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.