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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-61682
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-18 16:17:07 UTC
Updated2026-09-24 21:25:27 UTC
Descriptionkcp 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.

Risk And Classification

Primary CVSS: v3.1 9.9 CRITICAL from [email protected]

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

EPSS: 0.003840000 probability, percentile 0.296830000 (date 2026-09-25)

Problem Types: CWE-290 | CWE-302 | CWE-348 | CWE-290 CWE-290: Authentication Bypass by Spoofing | CWE-302 CWE-302: Authentication Bypass by Assumed-Immutable Data | CWE-348 CWE-348: Use of Less Trusted Source

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary9.9CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
3.1CNADECLARED9.9CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Kcp-dev Kcp affected < 0.31.4 Not specified
CNA Kcp-dev Kcp affected >= 0.32.0, < 0.32.2 Not specified

References

ReferenceSourceLinkTags
github.com/kcp-dev/kcp/releases/tag/v0.32.2 [email protected] github.com
github.com/kcp-dev/kcp/security/advisories/GHSA-c8w2-fgvx-vhv4 [email protected] github.com
github.com/kcp-dev/kcp/releases/tag/v0.31.4 [email protected] github.com
github.com/kcp-dev/kcp/commit/f913ee890fb2fd9fa78e50c43474b078bfb6aeff [email protected] github.com
github.com/kcp-dev/kcp/commit/7437cdcfec8f927d1a9bf1b2dd1e075d038e27ca [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report