PYSEC-2026-2689 ONNX has Null Pointer Dereference in Upsample Version Converter Adapter (Zero Inputs)

Summary Null pointer dereference SIGSEGV in Upsample67::adaptupsample67 onnx/versionconverter/adapters/upsample67.h:31 when convertversion processes a model with an Upsample node that has zero inputs. The adapter accesses node-inputs0-sizes without checking input count. 107-byte PoC crashes on...