CVE-2026-65835
MediumCVSS 6.6Exploitation Probability (EPSS)
Low risk9th percentile - higher than 9% of all known CVEs
Summary
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.
Risk Assessment
A Tenant Owner can escalate privileges and affect the entire Kubernetes cluster, breaking the multi-tenancy model and potentially leading to cluster compromise.
Recommendation
Upgrade Capsule to version 0.13.8 or later.
Other vulnerabilities in Capsule
See all- CVE-2026-22872Critical
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.
- CVE-2026-65834Medium
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.
- CVE-2026-30963Low
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.
Original NVD description (English source)
Capsule is a multi-tenancy and policy-based framework for Kubernetes. From 0.13.0 until 0.13.8, after the incomplete CVE-2026-22872 fix, TenantResource RawItems and Generators in internal/controllers/resources/collect.go, including handleRawItem and handleGeneratorItem, did not apply the ResourceReference.LoadResources and IsNamespacedGVK cluster-scoped resource rejection guard used by NamespacedItems, allowing a Tenant Owner to create cluster-scoped resources such as ClusterRole or ValidatingWebhookConfiguration through the cluster-admin controller client. This issue is fixed in version 0.13.8.