CVE-2026-55636

Capsule is a multi-tenancy and policy-based framework for Kubernetes. From 0.13.0 until 0.13.6, charts/capsule/templates/configuration.yaml configures the validating webhook with namespace/finalize instead of the Kubernetes resource name namespaces/finalize. A user with namespaces/finalize RBAC can send a PUT request to /api/v1/namespaces/{namespace}/finalize, and the singular rule never matches the plural resource, so the validating webhook is not invoked and the user can change the namespace tenant label. matchPolicy: Equivalent does not compensate because it handles API group and version equivalence rather than resource-name errors. This vulnerability is fixed in 0.13.6.

• https://github.com/projectcapsule/capsule/commit/af2f37793e789b2301da8ed8dfb52ab60affebb6
• https://github.com/projectcapsule/capsule/pull/1966
• https://github.com/projectcapsule/capsule/releases/tag/v0.13.6
• https://github.com/projectcapsule/capsule/security/advisories/GHSA-gwxr-7h77-7777