Argo Workflows versions prior to 4.0.2 and 3.7.11 allow any client to read WorkflowTemplates and ClusterWorkflowTemplates by sending an empty Authorization: Bearer token. The endpoint leaks the full template content, which can contain embedded Secret manifests. This unauthorized read leads to a clear data exposure scenario, where confidential configuration and credential information becomes accessible to attackers without authentication.

The vendor is argoproj and the product is argo-workflows. All releases running a version earlier than 4.0.2 or 3.7.11 are affected; any later release contains the fix.

The CVSS score of 9.8 marks the vulnerability as critical, while the EPSS score below 1% indicates that exploitation is currently unlikely but still possible. The vulnerability is not listed in the CISA KEV catalog. Attacks can be performed remotely by simply issuing an HTTP request to the WorkflowTemplates endpoint with an empty bearer token, which then returns sensitive template data to the attacker.