Executive brief
Argo Workflows, a container orchestration tool for Kubernetes, contains an authorization flaw in its archived workflow retrieval function. An attacker with permission to list workflows in one namespace can bypass access controls using a negated field selector to view archived workflows from all other namespaces, potentially exposing sensitive job parameters, values, and metadata.
Technical details
The ListArchivedWorkflows API endpoint fails to apply cluster-scoped authorization review when a metadata.namespace field selector uses the NotEquals operator, allowing an attacker with namespace-scoped list permissions to retrieve archived workflows outside their authorized namespace. The vulnerability exists because the normalization logic that switches to cluster-wide access checks for negated selectors was implemented for live workflows but missed in the archived workflow path. An attacker can construct a negated namespace field selector to enumerate and access archived workflows from unauthorized namespaces.
Affected products
- Argo Project Argo Workflows 4.1.0 through 4.1.3
Timeline
- 2026-09-19: disclosed