Kubeflow (AWS ALB Route Directive Adapter for Istio, OIDC JWT validation): The OIDC adapter that Kubeflow adopted for

Impact

The OIDC adapter that Kubeflow adopted for ALB-fronted deployments validates the JWT but never checks who signed or issued it. An attacker presents a token signed by their own key and is accepted as any federated user, which on Kubeflow means walking into another tenant's notebooks, pipelines and GPU quota. The upstream repo is deprecated and end of life, so no patch is coming.

Who can reach it

Any internet host that can reach an ALB target directly - that is, deployments where ALB targets are exposed rather than only reachable through the load balancer. No valid credentials required.

What to do

Stop using this adapter; it is end of life and unmaintained. Move Kubeflow authentication to a supported OIDC proxy (oauth2-proxy or the Istio authorization policies with a proper JWKS issuer pin), and make sure ALB target groups are only reachable from the load balancer, never directly.

References