Steeltoe vulnerable to management-port isolation bypass via spoofed Host header

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.2 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

EPSS

• CVE-2026-50194: 0.24% estimated exploitation activity in the next 30 days; percentile 14.91 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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:Port is configured to a value different from the application's main listener port. - The request scheme matches Management:Endpoints:SslEnabled. For example, http when SslEnabled is false (the default), or https when SslEnabled is true. 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…

Published by the source

2 Jul 2026, 20:29 UTC

Last modified by the source

2 Jul 2026, 20:29 UTC

Source last checked

26 Oct 2026, 17:04 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-58f6-6rj2-3v8r

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# Patch Next advisory brief: CVE-2026-50194

Advisory: Steeltoe vulnerable to management-port isolation bypass via spoofed Host header
IDs: CVE-2026-50194, GHSA-58f6-6rj2-3v8r
Record: https://patchnext.com/advisories/cve-2026-50194 (revision 1, source checked 26 Oct 2026, 17:04 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: steeltoe.management.endpoint 4.2.0; steeltoe.management.endpointcore 3.4.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet steeltoe.management.endpoint: affected <= 4.1.0; fixed in 4.2.0
- NuGet steeltoe.management.endpointcore: affected >= 3.2.2, <= 3.3.0; fixed in 3.4.0

## Suggested inspection (read-only)
- NuGet steeltoe.management.endpoint: check the installed version with your package manager.
- NuGet steeltoe.management.endpointcore: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on steeltoe.management.endpoint, steeltoe.management.endpointcore.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-58f6-6rj2-3v8r (GitHub-reviewed advisory GHSA-58f6-6rj2-3v8r lists affected ranges: NuGet steeltoe.management.endpoint >=0 =3.2.2 <=3.3.0)

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