Langflow is a tool for building and deploying AI-powered agents and workflows. From 1.0.0 until 1.10.1, Langflow did not verify flow ownership in the deprecated POST /api/v1/build/{flow_id}/vertices and POST /api/v1/build/{flow_id}/vertices/{vertex_id} handlers. Through version 1.7.1, an unauthenticated caller who knew another user's flow UUID could reach these handlers; from version 1.7.2 through 1.10.0, callers had to authenticate but needed no elevated privileges. Such a caller could cause retrieve_vertices_order to load and cache the private graph, enumerate its vertex identifiers, and use