kcp-dev kcp up to 0.31.3/0.32.1 front-proxy authorization

Summaryinfo

A vulnerability was found in kcp-dev kcp up to 0.31.3/0.32.1. It has been rated as very critical. This impacts an unknown function of the component front-proxy. The manipulation leads to authorization. This vulnerability is listed as CVE-2026-61682. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in kcp-dev kcp up to 0.31.3/0.32.1. This issue affects an unknown function of the component front-proxy. The manipulation with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. Impacted is confidentiality, integrity, and availability. The summary by CVE 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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-61682 since 07/10/2026. The exploitation is known to be easy. The attack may be initiated remotely. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/18/2026).

Upgrading to version 0.31.4 or 0.32.2 eliminates this vulnerability.

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Productinfo

Vendor

• kcp-dev

Name

• kcp

Version

• 0.31.0
• 0.31.1
• 0.31.2
• 0.31.3
• 0.32.0
• 0.32.1

Website

• Product: https://github.com/kcp-dev/kcp/

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