KubeSphere vulnerabilities

KubeSphere through 4.1.3 contains a server-side request forgery vulnerability in the git credential verification endpoint that accepts unvalidated caller-supplied URLs without allowlist restrictions. Authenticated attackers can supply arbitrary URLs to reach internal services and exfiltrate basic-auth credentials from Secrets in any namespace.

KubeSphere's cluster-controller reconciliation (pkg/utils/clusterclient/clusterclient.go, addCluster) processes every Cluster custom resource's connection configuration and immediately calls Discovery.ServerVersion against the CRD-specified Kubernetes API endpoint, which is parsed only for URL syntax (url.Parse) with no allow/deny-list for loopback, RFC1918 private ranges, link-local, or cloud-metadata addresses (e.g. 169.254.169.254).

The endpoint /v3/import/{token}_{clusterId}.yaml retrieves the cluster object before validating the token. When a valid cluster ID references a cluster with private registry secrets, a nil pointer dereference causes HTTP 502. For non-existent cluster IDs, it returns HTTP 200. This observable difference constitutes a reliable enumeration oracle.