A heap out-of-bounds memory write exists in FFMPEG since version 5.1. The size calculation in "build_open_gop_key_points()" goes through all entries in the loop and adds "sc->ctts_data[i].count" to "sc->sample_offsets_count". This can lead to an integer overflow resulting in a small allocation with "av_calloc()". An attacker can cause remote code execution via a malicious mp4 file. We recommend upgrading past commit c953baa084607dd1d84c3bfcce3cf6a87c3e6e05