FastGPT is an open source AI knowledge base platform. From 4.14.17 to before 4.15.0-beta4, FastGPT allows an authenticated tenant user to call POST /api/core/dataset/collection/create/reTrainingCollection in a way that persists a server-owned datasetId value from another tenant. This creates mixed dataset objects and downstream dataset, collection, and training endpoints then make authorization decisions from inconsistent ownership anchors, allowing cross-tenant read, update, and delete access when mixed object ids are known. This issue is fixed in version 4.15.0-beta4.