Capsule vulnerabilities

Vulnerability in Capsule, a multi-tenancy and policy-based framework for Kubernetes. The Capsule Controller runs with cluster-admin privileges. TenantResource RawItems processing incorrectly handles cluster-scoped resources, allowing tenant administrators to create cluster-scoped resources (e.g., ClusterRole, ValidatingWebhookConfiguration) with elevated privileges, leading to cross-tenant privilege escalation and cluster-level attacks. Version 0.13.0 patches this issue.

Capsule from 0.13.0 to 0.13.8 (after incomplete CVE-2026-22872 fix) did not apply cluster-scoped resource rejection guards, allowing a Tenant Owner to create cluster-scoped resources like ClusterRole or ValidatingWebhookConfiguration via the cluster-admin controller client.

Capsule before 0.13.8 did not validate regular expressions in CapsuleConfiguration for ForbiddenLabels and ForbiddenAnnotations. A Cluster Admin could store malformed regex that crashed the node admission webhook on node create, update, or patch requests.

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.