static int mov_read_header(AVFormatContext *s)
{
    MOVContext *mov = s->priv_data;
    AVIOContext *pb = s->pb;
    int err;
    MOVAtom atom = { AV_RL32("root") };

    mov->fc = s;
    /* .mov and .mp4 aren't streamable anyway (only progressive download if moov is before mdat) */
    if (pb->seekable)
        atom.size = avio_size(pb);
    else
        atom.size = INT64_MAX;

    /* check MOV header */
    if ((err = mov_read_default(mov, pb, atom)) < 0) {
        av_log(s, AV_LOG_ERROR, "error reading header: %d\n", err);
        mov_read_close(s);
        return err;
    }
    if (!mov->found_moov) {
        av_log(s, AV_LOG_ERROR, "moov atom not found\n");
        mov_read_close(s);
        return AVERROR_INVALIDDATA;
    }
    av_dlog(mov->fc, "on_parse_exit_offset=%"PRId64"\n", avio_tell(pb));

    if (pb->seekable) {
        int i;
        if (mov->chapter_track > 0)
            mov_read_chapters(s);
        for (i = 0; i < s->nb_streams; i++)
            if (s->streams[i]->codec->codec_tag == AV_RL32("tmcd"))
                mov_read_timecode_track(s, s->streams[i]);
    }

    if (mov->trex_data) {
        int i;
        for (i = 0; i < s->nb_streams; i++) {
            AVStream *st = s->streams[i];
            MOVStreamContext *sc = st->priv_data;
            if (st->duration)
                st->codec->bit_rate = sc->data_size * 8 * sc->time_scale / st->duration;
        }
    }

    return 0;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.