undefined-behavior in dvbsub parse clut segment

undefined-behavior in dvbsub parse clut segment: a task in MiMo-V2.6-RL-harbor-cyber: MiMo-V2.6-RL Cyber (Harbor) (Harbor dataset). UndefinedBehaviorSanitizer: undefined-behavior in function dvbsub parse clut segment in file ffmpeg/libavcodec/dvbsubdec.c