CVE-2026-30963

CVE-2026-30963 is a low-severity vulnerability in Projectcapsule Capsule with a CVSS 3.x base score of 3.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

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.

Frequently asked questions

What is CVE-2026-30963?
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.
How severe is CVE-2026-30963?
CVE-2026-30963 has a CVSS 3.x base score of 3.9, rated low severity. It is exploitable over network with high attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-30963 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-30963?
CVE-2026-30963 affects Projectcapsule Capsule. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-30963?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-30963 have an EU (EUVD) identifier?
Yes. CVE-2026-30963 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-33739.
When was CVE-2026-30963 published?
CVE-2026-30963 was published on 2026-06-01 and last updated on 2026-06-17.

References

Affected products (1)

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