The assisted‑service REST API in Red Hat Multicluster Engine exposes a credentials download endpoint (GET /v2/clusters/{cluster_id}/credentials) that returns the kubeadmin password and a kubeconfig file. In local authentication mode, any request that presents a valid locally issued JWT is granted full administrative rights across every endpoint, with no per‑endpoint restrictions. The JWT is embedded as a plain‑text query parameter in InfraEnvStatus.ISODownloadURL, which is readable by any user who has get rights on an InfraEnv object in their own namespace. Exploiting this flaw allows an authenticated user to retrieve the kubeadmin passphrase and kubeconfig for any OpenShift cluster provisioned through the hub, effectively giving them unrestricted root‑level control of those spoke clusters.

Affected systems include Red Hat Multicluster Engine for Kubernetes versions 2.1, 2.11, and 2.7, as well as any Advanced Cluster Management installations that incorporate MCE. The hosted SaaS offering (console.redhat.com) is not impacted because it uses a different authentication mode.

The CVSS base score of 6.1 indicates moderate severity; the EPSS score of < 1% (≈0.00014) indicates a very low likelihood of exploitation, and the vulnerability is not listed in the CISA KEV catalog. Because the flaw requires only minimal namespace‑scoped privileges to obtain a valid JWT, the likely attack vector is an insider or a compromised account with service‑principal or user permissions. In environments that rely on local authentication for on‑premises hubs, this can be executed without elevating privileges, thus representing a significant risk for organizations that deploy MCE in that mode.