Argo Workflows versions >=2.9.0 <4.0.2 and >=3.7.0 <3.7.11 contain an incorrect authorization vulnerability (CWE-863) where a user able to submit workflows can bypass security settings defined in WorkflowTemplates by including a podSpecPatch field in their workflow submission. This field takes precedence over the referenced WorkflowTemplate during spec merging and is applied directly to the pod spec without security validation, even when the controller is configured with templateReferencing: Strict. This allows the user to circumvent admin-approved template restrictions. The vulnerability is addressed in versions 4.0.2 and 3.7.11. The CVSS 4.0 score is 8.9 (high severity), indicating network attack vector, low attack complexity, partial privileges required, no user interaction, and high impacts on confidentiality, integrity, availability, scope, and security requirements.

An attacker with the ability to submit workflows can bypass all security controls defined in WorkflowTemplates by manipulating the podSpecPatch field. This can lead to unauthorized privilege escalation or execution of arbitrary pod specifications, undermining the intended security policies and potentially compromising the Kubernetes environment where Argo Workflows is deployed.

An official fix is available. Users should upgrade to argoproj argo-workflows versions 4.0.2 or 3.7.11 or later to remediate this vulnerability. Until upgraded, restricting workflow submission permissions and monitoring for unusual podSpecPatch usage may reduce risk, but patching is the definitive mitigation.