model.weights.h5: h5py.ExternalLink at Group level silently followed during load_model(), bypassing CVE-2025-9905 fix — information disclosure from arbitrary HDF5 files

Keras 3.x introduced a fix for CVE-2025-9905 by checking dataset.external in H5IOStore.verifydataset. This check blocks datasets whose raw bytes are stored in external files via the HDF5 "External Data Storage" mechanism. However, HDF5 supports a second, unrelated external-reference mechanism:...