GHSA-58f6-6rj2-3v8r Steeltoe vulnerable to management-port isolation bypass via spoofed Host header

• NuGet Steeltoe.Management.Endpoint: < 4.2.0 → fixed in 4.2.0 • NuGet Steeltoe.Management.EndpointCore: >= 3.2.2, < 3.4.0 → fixed in 3.4.0

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 proxy or load balancer to enforce the `Host` header value and prevent clients from setting an arbitrary port.