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Vulnerability · Published Jun 17, 2026 · Assigned by GitHub_M

CVE-2026-50194Steeltoe vulnerable to management-port isolation bypass via spoofed Host header

High 8.2

In plain English

A high-severity authentication bypass in Steeltoe.Management.Endpoint from SteeltoeOSS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.2High
Exploit odds (30 days)0.2%top 85.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. When Steeltoe management endpoints versions 3.2.2 through 3.3.0 and 4.1.0 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. Versions 3.4.0 and 4.2.0 patch the issue. 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 and/or configure the reverse proxy or load balancer to enforce the `Host` header value and prevent clients from setting an arbitrary port.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
NuGetsteeltoe.management.endpoint4.2.0GHSA-58f6-6rj2-3v8r
NuGetsteeltoe.management.endpointcore3.4.0GHSA-58f6-6rj2-3v8r

Affected products (as reported)

VendorProductVersions
SteeltoeOSS Steeltoe.Management.Endpoint < 4.2.0
SteeltoeOSS Steeltoe.Management.EndpointCore >= 3.2.2, < 3.4.0

Weakness: CWE-288, CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

References