CVE-2026-30963
LowCVSS 3.9Exploitation Probability (EPSS)
Low risk10th percentile - higher than 10% of all known CVEs
Summary
In Capsule for Kubernetes prior to 0.13.0, a vulnerability allowed namespace hijacking via namespace/finalize and namespace/status subresources. The validating webhook does not intercept these subresources, allowing a tenant admin to modify namespace metadata.
Risk Assessment
A tenant admin can hijack namespaces, breaking multi-tenancy isolation and potentially leaking data.
Recommendation
Update Capsule to version 0.13.0 or add namespace/finalize and namespace/status to the resources list in ValidatingWebhookConfiguration rules.
Original NVD description (English source)
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.