MP4Box is a component of GPAC-2.0.0 which is a widely-used third-party package on RPM Fusion. When MP4Box tries to parse a MP4 file it calls the function `diST_box_read()` to read from video. In this function it allocates a buffer `str` with fixed length. However content read from `bs` is controllable by user so is the length which causes a buffer overflow.