What’s Vulnerable › Vulnerabilities

CVE-2026-61682: kcp front-proxy does not strip inbound X-Remote-* identity headers, allowing any authenticated client to inject groups/warrants and impersonate system:masters in any workspace

• Severity: critical (CVSS 9.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-18 · updated 2026-09-24
• Weakness: CWE-290

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.

Affected products

• kcp-dev kcp: before 0.31.4; from 0.32.0, < 0.32.2

References

• https://github.com/kcp-dev/kcp/commit/7437cdcfec8f927d1a9bf1b2dd1e075d038e27ca
• https://github.com/kcp-dev/kcp/commit/f913ee890fb2fd9fa78e50c43474b078bfb6aeff
• https://github.com/kcp-dev/kcp/releases/tag/v0.31.4
• https://github.com/kcp-dev/kcp/releases/tag/v0.32.2
• https://github.com/kcp-dev/kcp/security/advisories/GHSA-c8w2-fgvx-vhv4

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