Vulnerability 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.
CVSS Score
LOW
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Projectcapsule | Capsule | < 0.13.0 |
Related Weaknesses (CWE)
References
- https://github.com/projectcapsule/capsule/releases/tag/v0.13.0ProductRelease Notes
- https://github.com/projectcapsule/capsule/security/advisories/GHSA-2ww6-hf35-mfjExploitMitigationVendor Advisory
- https://github.com/projectcapsule/capsule/security/advisories/GHSA-2ww6-hf35-mfjExploitMitigationVendor Advisory
FAQ
What is CVE-2026-30963?
CVE-2026-30963 is a vulnerability with a CVSS score of 3.9 (LOW). 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 u...
How severe is CVE-2026-30963?
CVE-2026-30963 has been rated LOW with a CVSS base score of 3.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-30963?
Check the references section above for vendor advisories and patch information. Affected products include: Projectcapsule Capsule.