CVE-2019-0545 — Microsoft.NETCore.App
HIGHCVE-2019-0545 is a high-severity (CVSS 7.5) Information Exposure vulnerability in Microsoft.NETCore.App. A fix is available for Microsoft.NETCore.App — see the affected versions and patch details below.
Exposure of Sensitive Information in System.Net.Http
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
Microsoft.NETCore.App.NETMicrosoft.NETCore.AppReal-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
An information disclosure vulnerability exists in .NET Framework and .NET Core which allows bypassing Cross-origin Resource Sharing (CORS) configurations, aka ".NET Framework Information Disclosure Vulnerability." This affects Microsoft .NET Framework 2.0, Microsoft .NET Framework 3.0, Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2, Microsoft .NET Framework 4.5.2, Microsoft .NET Framework 4.6, Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2, Microsoft .NET Framework 4.7/4.7.1/4.7.2, .NET Core 2.1, Microsoft .NET Framework 4.7.1/4.7.2, Microsoft .NET Framework 3.5, Microsoft .NET Framework 3.5.1, Microsoft .NET Framework 4.6/4.6.1/4.6.2, .NET Core 2.2, Microsoft .NET Framework 4.7.2.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.NETCore.App | ≥ 2.1.0&&< 2.1.7 | 2.1.7dotnet add package Microsoft.NETCore.App --version 2.1.7 |
| .NETNuGet | Microsoft.NETCore.App | ≥ 2.2.0&&< 2.2.1 | 2.2.1dotnet add package Microsoft.NETCore.App --version 2.2.1 |
Affected Products
.net coremicrosoft.net frameworkmicrosoftDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.NETCore.App, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Microsoft.NETCore.App to 2.1.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-0545 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.
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-dotnet21-0:2.1-6.el7 | RHSA-2019:0040 |
Frequently Asked Questions
Is CVE-2019-0545 in your dependencies?
Find it across NuGet, including transitive dependencies.