static int mov_read_trex(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    MOVTrackExt *trex;

    if ((uint64_t)c->trex_count+1 >= UINT_MAX / sizeof(*c->trex_data))
        return AVERROR_INVALIDDATA;
    trex = av_realloc(c->trex_data, (c->trex_count+1)*sizeof(*c->trex_data));
    if (!trex)
        return AVERROR(ENOMEM);

    c->fc->duration = AV_NOPTS_VALUE; // the duration from mvhd is not representing the whole file when fragments are used.

    c->trex_data = trex;
    trex = &c->trex_data[c->trex_count++];
    avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */
    trex->track_id = avio_rb32(pb);
    trex->stsd_id  = avio_rb32(pb);
    trex->duration = avio_rb32(pb);
    trex->size     = avio_rb32(pb);
    trex->flags    = avio_rb32(pb);
    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.