CVE-2026-61682: Kcp-Dev Kcp

Critical severity, CVSS 9.9. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Kcp-Dev Kcp: before 0.31.4 (fixed in 0.31.4); from 0.32.0, before 0.32.2 (fixed in 0.32.2)

Published 2026-09-18. Last modified 2026-09-24.