CVE-2026-61682

Critical

Description

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.

SeverityCritical
CVSS9.9
Exploit probability—
ProductGithub.com/kcp-dev/kcp
PublishedSep 18, 2026
First seenSep 18, 2026

How to fix

Update
  • github.com/kcp-dev/kcp0.31.4, 0.32.2 or later

Affected products

ProductAffected versionsFixed in
github.com/kcp-dev/kcpGov < 0.31.4, 0.32.0 ≤ v < 0.32.20.31.4, 0.32.2

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