heap-buffer-overflow in unpack bstr

heap-buffer-overflow in unpack bstr: a task in MiMo-V2.6-RL-harbor-cyber: MiMo-V2.6-RL Cyber (Harbor) (Harbor dataset). AddressSanitizer: heap-buffer-overflow in function unpack bstr in file mruby/mrbgems/mruby-pack/src/pack.c