CVE-2026-50194 is a high-severity (CVSS 8.2) CWE-288 vulnerability in Steeltoe.Management.Endpoint. A fix is available for Steeltoe.Management.Endpoint — see the affected versions and patch details below.
Steeltoe vulnerable to management-port isolation bypass via spoofed Host header
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-50194.
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
Steeltoe.Management.Endpoint.NETSteeltoe.Management.EndpointCoreReal-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
Summary
When Steeltoe management endpoints are configured to listen on an alternate port (Management:Endpoints:Port is configured), the middleware responsible for restricting access to the endpoints uses the Host HTTP header rather than the actual network socket port.
Impact
An unauthenticated remote attacker can reach every actuator endpoint using a specially crafted HTTP request.
Affected configuration
- The application's public port is accessible over from the network.
Management:Endpoints:Portis configured to a value different from the application's main listener port.- The request scheme matches
Management:Endpoints:SslEnabled. For example,httpwhenSslEnabledisfalse(the default), orhttpswhenSslEnabledistrue.
Mitigations
If an immediate upgrade to a patched version is not possible:
- Add explicit ASP.NET Core authorization (
RequireAuthorization) to all sensitive actuator endpoints as a defense-in-depth measure independent of port isolation. - Configure the reverse proxy or load balancer to enforce the
Hostheader value and prevent clients from setting an arbitrary port.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Steeltoe.Management.Endpoint | all versions | 4.2.0dotnet add package Steeltoe.Management.Endpoint --version 4.2.0 |
| .NETNuGet | Steeltoe.Management.EndpointCore | ≥ 3.2.2&&< 3.4.0 | 3.4.0dotnet add package Steeltoe.Management.EndpointCore --version 3.4.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Steeltoe.Management.Endpoint, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Steeltoe.Management.Endpoint to 4.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-50194 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.
Frequently Asked Questions
Is CVE-2026-50194 in your dependencies?
Find it across NuGet, including transitive dependencies.