GHSA-f8qx-mjcq-wfgx — Microsoft.AspNetCore.App
HIGHGHSA-f8qx-mjcq-wfgx is a high-severity (CVSS 7.5) vulnerability in Microsoft.AspNetCore.App. A fix is available for Microsoft.AspNetCore.App — see the affected versions and patch details below.
ASP.NET Core Denial of Service Vulnerability
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-f8qx-mjcq-wfgx plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
Microsoft.AspNetCore.App.NETMicrosoft.AspNetCore.All.NETMicrosoft.AspNetCore.App.Runtime.linux-arm.NETMicrosoft.AspNetCore.App.Runtime.linux-arm64.NETMicrosoft.AspNetCore.App.Runtime.linux-musl-arm64.NETMicrosoft.AspNetCore.App.Runtime.linux-musl-x64.NETMicrosoft.AspNetCore.App.Runtime.linux-x64.NETMicrosoft.AspNetCore.App.Runtime.osx-x64+4 moreReal-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
A denial of service vulnerability exists when ASP.NET Core improperly handles web requests, aka ASP.NET Core Denial of Service Vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.AspNetCore.App | ≥ 2.1.0&&< 2.1.21 | 2.1.21dotnet add package Microsoft.AspNetCore.App --version 2.1.21 |
| .NETNuGet | Microsoft.AspNetCore.All | ≥ 2.1.0&&< 2.1.21 | 2.1.21dotnet add package Microsoft.AspNetCore.All --version 2.1.21 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-arm | ≥ 3.1.0&&< 3.1.7 | 3.1.7dotnet add package Microsoft.AspNetCore.App.Runtime.linux-arm --version 3.1.7 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-arm64 | ≥ 3.1.0&&< 3.1.7 | 3.1.7dotnet add package Microsoft.AspNetCore.App.Runtime.linux-arm64 --version 3.1.7 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | ≥ 3.1.0&&< 3.1.7 | 3.1.7dotnet add package Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 --version 3.1.7 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | ≥ 3.1.0&&< 3.1.7 | 3.1.7dotnet add package Microsoft.AspNetCore.App.Runtime.linux-musl-x64 --version 3.1.7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.AspNetCore.App, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Microsoft.AspNetCore.App to 2.1.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f8qx-mjcq-wfgx 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-f8qx-mjcq-wfgx can be triaged on real exposure rather than presence alone.
Tailored to GHSA-f8qx-mjcq-wfgx. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| .NET Core on Red Hat Enterprise Linux | rh-dotnet31-dotnet-0:3.1.107-1.el7 | RHSA-2020:3421 |
| Red Hat Enterprise Linux 8 | dotnet3.1-0:3.1.107-1.el8_2 | RHSA-2020:3422 |
Frequently Asked Questions
Is GHSA-f8qx-mjcq-wfgx in your dependencies?
O3 Security finds GHSA-f8qx-mjcq-wfgx across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.