CVE-2026-2270 in Kubernetes
Summary
by MITRE • 10/27/2026
A confused deputy attack exists in the StatefulSet controller that allows a user with namespace-scoped write permissions on StatefulSet and ControllerRevision objects to create a cross-namespace pod. An attacker exploiting this vulnerability would have full control over the resulting pod’s metadata and specification, including namespace selection. Note that the cross-namespace pod will be immediately deleted by the garbage collector unless the attacker is able to construct a valid StatefulSet OwnerReference. This would require referencing the UID of an existing StatefulSet in the victim’s namespace.
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Analysis
by VulDB Data Team • 10/27/2026
The vulnerability described constitutes a confused deputy attack within the Kubernetes StatefulSet controller, representing a significant escalation path for attackers who possess limited permissions. In this scenario, an adversary with write access to StatefulSet and ControllerRevision objects within their own namespace can manipulate the control plane logic to spawn pods in namespaces where they lack direct authorization. This flaw arises from insufficient validation of cross-references during the reconciliation process, allowing a user-controlled object to influence resources outside its designated boundary. The core technical issue lies in how the controller resolves owner references and validates namespace scoping when creating dependent pod objects. By crafting specific metadata structures, an attacker can trick the StatefulSet controller into believing that a pod should be created under the authority of a resource located in a different namespace than where the user has permission to operate.
The operational impact of this vulnerability is severe because it grants the attacker full control over the resulting pod’s metadata and specification. This includes the ability to select the target namespace, effectively bypassing namespace isolation policies that are fundamental to multi-tenant Kubernetes environments. If successful, the attacker can deploy workloads in sensitive namespaces such as kube-system or other critical infrastructure areas, potentially leading to cluster-wide compromise, data exfiltration, or lateral movement across service boundaries. However, there is a notable constraint on this attack vector: the cross-namespace pod created by the controller will be immediately deleted by the garbage collector unless specific conditions are met. The attacker must construct a valid StatefulSet OwnerReference that correctly references the UID of an existing StatefulSet in the victim’s namespace. This requirement adds complexity to the exploitation, as it necessitates prior knowledge or discovery of resource UIDs within the target namespace, which may be mitigated by strict RBAC policies preventing enumeration of such identifiers.
From a classification perspective, this vulnerability aligns with CWE-269, Improper Privilege Management, specifically involving confusion between different security contexts and authorities. It also maps to MITRE ATT&CK techniques related to privilege escalation and lateral movement within containerized environments, particularly those exploiting misconfigured access controls or logic flaws in orchestration layers. The attack leverages the principle of least privilege violation by allowing a lower-privileged actor to perform actions reserved for higher-privileged entities through indirect manipulation of controller behavior rather than direct permission grants.
Mitigation strategies should focus on tightening RBAC policies and enhancing validation mechanisms within the control plane. Administrators should ensure that users do not have write access to StatefulSet objects unless absolutely necessary, as this is the primary vector for exploitation. Additionally, implementing network policies can help limit lateral movement even if a pod is successfully spawned in an unintended namespace. Upgrading to patched versions of Kubernetes where this logic flaw has been addressed by the maintainers is critical. Furthermore, auditing and monitoring for unusual patterns in StatefulSet creation events or unexpected cross-namespace resource references can aid in early detection of such exploitation attempts. Regular review of service account permissions and adherence to strict least-privilege principles will reduce the attack surface available to potential adversaries seeking to exploit this confused deputy scenario.