CVE-2026-22872: Capsule TenantResource RawItems Cluster-Scoped Resource Creation Vulnerability

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-01 · updated 2026-07-22
Weakness: CWE-20

Description

Capsule is a multi-tenancy and policy-based framework for Kubernetes. The Capsule Controller runs with cluster-admin privileges. Although the TenantResource RawItems processing logic forcibly sets the namespace, this is ineffective for cluster-scoped resources. Prior to version 0.13.0, tenant administrators can leverage the Controller's elevated privileges to create cluster-scoped resources (such as ClusterRole and ValidatingWebhookConfiguration) that they cannot create directly, achieving cross-tenant privilege escalation and cluster-level attacks. The attack vector has a few limiting factors. This attack requires Tenant Owner privileges and requires Capsule Controller running with cluster-admin privileges (default configuration). Additionally, some clusters may have additional admission controllers blocking malicious resources. Version 0.13.0 patches this issue.

Affected products

projectcapsule capsule: before 0.13.0 — fixed in 0.13.0

How to fix

Upgrade to a fixed version: projectcapsule capsule 0.13.0. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-22872 or the next vulnerability affects your stack