CVE-2026-30963
Capsule Namespace Hijacking via subresource
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.
- Affected
- projectcapsule · capsule
- CVSS v3.1 NVD
- 2.7 LOW
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:N - CVSS v3.1 GITHUB
- 3.9 LOW
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:L - EPSS
- 0.25% chance of exploitation in the next 30 days, 16th percentile
- Published
- 2026-06-01
- Updated
- 2026-06-02
Proof-of-concept exploits (1)
Security advisories
- projectcapsule/capsule/security/advisories/GHSA-2ww6-hf35-mfjm
- projectcapsule/capsule/releases/tag/v0.13.0