GPUStack: Missing authorization on several cluster and resource endpoints allows cross-user access and cluster takeover

Summary

GPUStack is an open-source GPU cluster manager for AI model serving and GPU instance provisioning. From 2.2.0 until 2.2.2, cluster_apiserver_proxy forwarded an authenticated non-administrator's requests to a selected Kubernetes cluster without a resource-level authorization check. The proxy used a reachable worker's Kubernetes ServiceAccount credentials, so the caller could read sensitive resources, create or modify workloads, or delete resources according to that ServiceAccount's permissions. Exploitation required a Kubernetes-provider cluster with a reachable worker, and attacker-controlled workloads could result in code execution in the target cluster. This issue is fixed in version 2.2.2.

Remediation

1. Inventory every gpustack gpustack deployment, including staging.
2. No fixed version appears in the public sources yet. Check the references below and the vendor directly.

References

• Referencehttps://github.com/gpustack/gpustack/commit/363191fa1da7e1426c6041f78b3cf00aff2622fe
• Referencehttps://github.com/gpustack/gpustack/commit/cdd67467e0f314609dc82216e142940d321abfed
• Referencehttps://github.com/gpustack/gpustack/pull/5911
• Referencehttps://github.com/gpustack/gpustack/pull/5936
• Referencehttps://github.com/gpustack/gpustack/releases/tag/v2.2.2
• Referencehttps://github.com/gpustack/gpustack/security/advisories/GHSA-3hch-x692-6qj3