CVE-2026-122302 in Kyverno
Summary
by MITRE • 11/05/2026
Kyverno before 1.19.2 contains a privilege escalation vulnerability that allows namespace admins to create resources beyond their RBAC because generate-rule admission checks verify the controller's permissions, not the author's. Attackers can create a namespaced Policy with generate rules targeting other namespaces or cluster-scoped kinds, making the background controller create or clone resources cluster-wide.
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Analysis
by VulDB Data Team • 11/05/2026
The vulnerability identified in Kyverno versions prior to 1.19.2 represents a critical flaw in the access control logic governing policy generation and enforcement mechanisms within Kubernetes environments. This issue stems from an incorrect verification of permissions during the admission process for policies containing generate rules. Specifically, when a user submits a namespaced Policy object that includes generate rules intended to create or clone resources across other namespaces or targeting cluster-scoped kinds, Kyverno’s admission webhook validates whether the service account running the background controller possesses the necessary privileges to perform these actions. It fails to verify if the submitting user has explicit RBAC permissions for those specific target resources and scopes. This architectural oversight creates a significant gap between the intended security boundaries defined by Kubernetes Role-Based Access Control policies and the actual operational capabilities granted through Kyverno’s policy engine.
From a technical perspective, this flaw allows namespace administrators who are otherwise restricted from modifying cluster-wide configurations to bypass these restrictions indirectly. By crafting a malicious or misconfigured Policy resource with generate rules that target high-privilege resources such as ClusterRoles, PersistentVolumeClaims in other namespaces, or even service accounts in the kube-system namespace, an attacker can leverage the Kyverno controller’s elevated privileges to execute these actions on their behalf. The background controller operates with cluster-admin level permissions by design to enforce policies effectively, and this vulnerability exploits that trust relationship. Consequently, a user who should only have read-only access within their designated namespace gains the ability to create, modify, or delete resources across the entire cluster without direct authorization from the Kubernetes API server’s RBAC layer.
The operational impact of this privilege escalation is severe, potentially leading to full cluster compromise. An attacker could use this vector to escalate privileges by creating new service accounts with elevated roles in critical namespaces, thereby establishing persistent access and lateral movement capabilities within the environment. Furthermore, they could disrupt operations by deleting essential system components or exfiltrate sensitive data from restricted namespaces that were previously inaccessible. This type of vulnerability aligns closely with CWE-269 Improper Privilege Management, as it involves a failure to enforce proper authorization checks before granting elevated actions. In terms of the MITRE ATT&CK framework for Kubernetes, this behavior corresponds to T1098.004 SSH Authorized Keys which describes unauthorized account modification and more broadly fits within lateral movement techniques where an attacker uses compromised credentials or permissions to move across different parts of the infrastructure by exploiting trust relationships between services.
To mitigate this risk, organizations running Kyverno must immediately upgrade to version 1.19.2 or later, where the admission logic has been corrected to verify the submitting user’s RBAC permissions against the target resources specified in generate rules rather than relying solely on the controller’s privileges. In addition to upgrading, administrators should implement strict least-privilege principles for Kyverno service accounts and regularly audit policy definitions for any that contain cross-namespace or cluster-scoped targets unless absolutely necessary. Monitoring tools such as Falco or OPA Gatekeeper can be configured to detect anomalous resource creation patterns originating from namespace-level users attempting to interact with cluster-wide resources, providing an additional layer of defense against exploitation attempts while the upgrade is being deployed across the infrastructure.