Executive brief
External Secrets Operator is a Kubernetes tool that integrates third-party secret management services like AWS Secrets Manager into Kubernetes. A vulnerability was found where a user in one project (namespace) could access security certificates belonging to another project. While this does not directly expose sensitive passwords, it allows unauthorized users to verify the existence of resources in other projects and potentially interfere with secure connections.
Technical details
A namespace isolation bypass exists in External Secrets Operator when using CAProvider with type ConfigMap. Namespaced SecretStore resources could resolve CA material from a different namespace if the caProvider.namespace field was explicitly set, bypassing the intended security boundary enforced by the shared runtime CA resolver. An attacker with low privileges can exploit this to infer the existence of ConfigMaps or keys in other namespaces or force a SecretStore to consume unauthorized CA material. The vulnerability is patched in version 2.4.0.
Affected products
- external-secrets external-secrets < 2.4.0
Timeline
- 2026-04-24: disclosed: Vulnerability reported by moolen
- 2026-05-05: advisory: GitHub Advisory published
- 2026-05-11: other: NVD publication date