Threat Intelligence Database

### Summary When Steeltoe's certificate-based authorization (`UseCertificateAuthorization`) is configured, the default configuration of the middleware relies on the `X-Client-Cert` HTTP header to identify the client certificate, without verifying private-key possession. This header is not stripped by common Cloud Foundry routers (like Gorouter or Envoy) on inbound requests. ### Impact An attacker who obtains the public certificate of an application instance in the target organization or space can spoof the `X-Client-Cert` header. This allows the attacker to bypass `SameOrg` and `SameSpace` authorization policies, granting unauthorized access to protected endpoints for the duration of the certificate's validity period. ### Affected configuration - The application uses `AddOrgAndSpacePolicies()` and `UseCertificateAuthorization()` for inter-service authorization. - Inbound requests are not restricted to a known trusted proxy source IP. - The application's endpoints are network-accessible to the attacker (e.g., exposed to the internet via a public Cloud Foundry route, or the attacker has access to the internal Cloud Foundry network). ### Mitigations If an immediate upgrade to a patched version is not possible: - Restrict `UseCertificateForwarding` to trusted proxy source IPs using `ForwardedHeadersOptions.KnownProxies` and `KnownNetworks`. - Change the forwarding header to `X-Forwarded-Client-Cert` so that Cloud Foundry Gorouter and Envoy header stripping mechanisms apply to inbound untrusted requests. - Add a secondary authorization layer (e.g., a shared secret or mutual TLS at the proxy layer) for sensitive endpoints. - Ensure the application is not bound to a public route unless explicitly required. Use Cloud Foundry internal routes (e.g., `.apps.internal`) and container-to-container network policies to strictly limit network access to intended internal clients.

## Summary Steeltoe's Eureka discovery client deserializes the registry response as a single unit. If any registered instance contains a field value that cannot be parsed (for example, an unrecognized `actionType`, a non-boolean value for `isCoordinatingDiscoveryServer`, or a non-numeric timestamp), deserialization of the entire registry fails. All Steeltoe Eureka clients connected to that registry then receive an empty or stale instance list until the malformed registration is removed. This is a related but distinct issue from [CVE-2026-50196](https://github.com/advisories/GHSA-j8ph-6fxj-g533), which addressed only the `DataCenterInfo.name` field. ## Impact Any principal that can register or update a service instance in the Eureka registry can trigger a service-discovery outage for all Steeltoe applications connected to the same registry. The outage persists until the offending registration is removed. ## Affected configuration * Application uses `EurekaDiscoveryClient` (any deployment, including self-hosted Eureka). * The registry contains at least one service instance with an unrecognized value in a field such as `actionType`, `status`, `isCoordinatingDiscoveryServer`, or timestamp fields. * Mixed-platform environments — for example, Java or Spring services co-existing in the same Eureka registry — are more likely to encounter this condition. ## Mitigations If an immediate upgrade is not possible: * Audit the Eureka registry for registrations containing non-standard field values, particularly those originating from non-.NET clients. * Restrict write access to the Eureka registration API to trusted services.