OpenShift Router EUVD-2026-33275

Requires an authenticated OpenShift user (PR:L) with RBAC permission to create or update EndpointSlice (and typically Service/Route) objects in at least one namespace on a target OpenShift Container Platform 4 cluster; the cluster must be deployed on a cloud provider exposing an instance metadata service reachable from the router pods (e.g., AWS, Azure, GCP) - on-premise clusters without such an endpoint are not exploitable for credential disclosure. The attack uses an FQDN-typed EndpointSlice resolving to the metadata IP, which specifically bypasses the prior IP-validation mitigation, so clusters that had the earlier IP-block fix remain vulnerable until this fix is applied. No user interaction is required (UI:N), and exploitation is constrained to information disclosure (C:H/I:N/A:N) - the attacker cannot directly modify router behavior or cause denial of service through this flaw.

The CVSS 7.7 (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N) reflects a network-reachable, low-complexity attack requiring low privileges, with a scope change and high confidentiality impact - consistent with SSRF leaking cloud credentials across a trust boundary. The real-world risk depends heavily on who holds EndpointSlice write permission: in well-segmented clusters this is restricted to cluster admins or specific namespaces, but multi-tenant OpenShift deployments commonly grant project-level users sufficient permissions to create Services and Endpoints, making PR:L realistic. EPSS data was not provided and CISA KEV does not list this CVE, so there is no public exploit identified at time of analysis; however, SSRF-to-metadata is a well-understood, automatable pattern, and obtaining cloud IAM credentials from a compromised cluster typically enables significant lateral movement. Treat this as a high priority on cloud-hosted OpenShift clusters that grant broad EndpointSlice/Service permissions; on-premise clusters without a metadata service are materially less exposed.

An attacker with a low-privileged OpenShift account that holds EndpointSlice write permission in any namespace creates a Service plus an EndpointSlice whose addressType is FQDN and whose endpoint resolves (via attacker-controlled DNS or a public record) to 169.254.169.254. The attacker then sends an HTTP request through the cluster's exposed Router to a route mapped at that Service; the router proxies the request to the cloud metadata endpoint and returns IAM credentials for the underlying node, which the attacker uses to pivot into the cloud account.