CVE-2019-1075 — Microsoft.AspNetCore.App
MEDIUMCVE-2019-1075 is a medium-severity (CVSS 6.1) Open Redirect vulnerability in Microsoft.AspNetCore.App. A fix is available for Microsoft.AspNetCore.App — see the affected versions and patch details below.
Open redirect in ASP.NET Core
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
CVE-2019-1075 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.App.NETMicrosoft.AspNetCore.All.NETMicrosoft.AspNetCore.All.NETMicrosoft.AspNetCore.Server.IIS.NETMicrosoft.AspNetCore.Server.HttpSys.NETMicrosoft.AspNetCore.Server.HttpSysReal-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 spoofing vulnerability exists in ASP.NET Core that could lead to an open redirect, aka 'ASP.NET Core Spoofing Vulnerability'.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.AspNetCore.App | ≥ 2.2.0&&< 2.2.6 | 2.2.6dotnet add package Microsoft.AspNetCore.App --version 2.2.6 |
| .NETNuGet | Microsoft.AspNetCore.App | ≥ 2.1.0&&< 2.1.12 | 2.1.12dotnet add package Microsoft.AspNetCore.App --version 2.1.12 |
| .NETNuGet | Microsoft.AspNetCore.All | ≥ 2.2.0&&< 2.2.6 | 2.2.6dotnet add package Microsoft.AspNetCore.All --version 2.2.6 |
| .NETNuGet | Microsoft.AspNetCore.All | ≥ 2.1.0&&< 2.1.12 | 2.1.12dotnet add package Microsoft.AspNetCore.All --version 2.1.12 |
| .NETNuGet | Microsoft.AspNetCore.Server.IIS | ≥ 2.2.0&&< 2.2.6 | 2.2.6dotnet add package Microsoft.AspNetCore.Server.IIS --version 2.2.6 |
| .NETNuGet | Microsoft.AspNetCore.Server.HttpSys | ≥ 2.2.0&&< 2.2.6 | 2.2.6dotnet add package Microsoft.AspNetCore.Server.HttpSys --version 2.2.6 |
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 2.2.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-1075 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 CVE-2019-1075 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2019-1075. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2019-1075 in your dependencies?
O3 Security finds CVE-2019-1075 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.