CVE-2026-61682

CriticalCVSS 9.9

Published: 18/09/2026(UTC)Translated: 18/09/2026(UTC)NVD NIST

Summary

kcp before 0.31.4 and 0.32.2 fails to strip inbound identity headers (X-Remote-User, X-Remote-Group, X-Remote-Extra-*) before forwarding requests to shards. Any authenticated tenant can inject X-Remote-Group: system:masters, gaining full privileges.

Risk Assessment

An attacker can impersonate other identities, bypass authorization, and read/write/delete resources, secrets, RBAC data, APIExports, APIBindings, and LogicalClusters.

Recommendation

Upgrade kcp to version 0.31.4 or 0.32.2, which remove these headers.

Other vulnerabilities in kcp

CVE-2026-39429High
kcp before versions 0.30.3 and 0.29.3 exposes the cache server directly via the root shard without authentication. Anyone with access to the root shard can read and write to the cache.

Original NVD description (English source)

kcp is a Kubernetes-like control plane for form-factors and use-cases beyond Kubernetes and container workloads. Prior to 0.31.4 and 0.32.2, the kcp front-proxy does not remove inbound X-Remote-User, X-Remote-Group, or X-Remote-Extra-* identity headers before forwarding requests to shards. Any authenticated tenant can inject X-Remote-Group: system:masters, authorization.kcp.io/warrant, authentication.kcp.io/scopes, or a group used for per-workspace required-group gating, and the shard trusts these values as authenticated identity assertions. This allows cross-workspace impersonation, authorization bypass, and arbitrary reading, writing, or deletion of resources, secrets, RBAC data, APIExports, APIBindings, and LogicalClusters. This issue is fixed in versions 0.31.4 and 0.32.2.