CVE-2026-61682

Critical CVSS 9.9

Published 2026-09-18 · last changed 2026-09-18

The fix

We hold no Microsoft remediation data for CVE-2026-61682, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

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.

Sources

NVD record for CVE-2026-61682

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H