Capsule is a multi-tenancy and policy-based framework for Kubernetes. To defend against namespace hijacking achieved through update/patch operations on namespaces, Capsule uses a webhook to validate update requests targeting namespaces. However, in Kubernetes, the namespace/finalize and namespace/status subresource APIs can also modify various fields of a namespace, including the metadata field. Prior to version 0.13.0, the webhook does not define interception rules for these subresources. As a result, if a tenant administrator has permission to modify namespace/status or namespace/finalize, they can successfully perform namespace hijacking. Version 0.13.0 fixes the issue. Another mitigation is to add two subresources (namespaces and snamespaces/status with namespace/finalize within it) to the resources list in the ValidatingWebhookConfiguration rules.
History

Mon, 01 Jun 2026 20:45:00 +0000

Type Values Removed Values Added
First Time appeared Projectcapsule
Projectcapsule capsule
Vendors & Products Projectcapsule
Projectcapsule capsule

Mon, 01 Jun 2026 19:00:00 +0000

Type Values Removed Values Added
Description Capsule is a multi-tenancy and policy-based framework for Kubernetes. To defend against namespace hijacking achieved through update/patch operations on namespaces, Capsule uses a webhook to validate update requests targeting namespaces. However, in Kubernetes, the namespace/finalize and namespace/status subresource APIs can also modify various fields of a namespace, including the metadata field. Prior to version 0.13.0, the webhook does not define interception rules for these subresources. As a result, if a tenant administrator has permission to modify namespace/status or namespace/finalize, they can successfully perform namespace hijacking. Version 0.13.0 fixes the issue. Another mitigation is to add two subresources (namespaces and snamespaces/status with namespace/finalize within it) to the resources list in the ValidatingWebhookConfiguration rules.
Title Capsule Namespace Hijacking via subresource
Weaknesses CWE-20
References
Metrics cvssV3_1

{'score': 3.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:L'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-01T18:00:43.797Z

Reserved: 2026-03-07T17:53:48.814Z

Link: CVE-2026-30963

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-06-01T19:16:22.780

Modified: 2026-06-01T19:16:22.780

Link: CVE-2026-30963

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-01T20:30:17Z