CVE-2026-88983: Kubeflow Pipelines — API server fetches a caller-supplied pipelineURL without host validation

Kubeflow Pipelines enables users to build and deploy portable, scalable machine learning workflows. Prior to 2.17.0, the API server's pipeline and pipeline-version creation paths fetch a caller-supplied pipelineURL without restricting the destination. An authenticated caller with permission to create a pipeline or pipeline version can make requests from the API server to internal services and observe a limited status-code oracle. Arbitrary response-body disclosure, credential theft, and integrity or availability impact are not established. This issue is fixed in version 2.17.0.