heap-buffer-overflow in m3d safestr

heap-buffer-overflow in m3d safestr: a task in MiMo-V2.6-RL-oss: Agentic RL Environments (MiMo RL release). AddressSanitizer: heap-buffer-overflow in function m3d safestr in file assimp/code/AssetLib/M3D/m3d.h