static int mov_read_ctts(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    unsigned int i, entries;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */
    entries = avio_rb32(pb);

    av_dlog(c->fc, "track[%i].ctts.entries = %i\n", c->fc->nb_streams-1, entries);

    if (!entries)
        return 0;
    if (entries >= UINT_MAX / sizeof(*sc->ctts_data))
        return AVERROR_INVALIDDATA;
    sc->ctts_data = av_malloc(entries * sizeof(*sc->ctts_data));
    if (!sc->ctts_data)
        return AVERROR(ENOMEM);
    sc->ctts_count = entries;

    for (i=0; i<entries; i++) {
        int count    =avio_rb32(pb);
        int duration =avio_rb32(pb);

        sc->ctts_data[i].count   = count;
        sc->ctts_data[i].duration= duration;

        if (FFABS(duration) > (1<<28) && i+2<entries) {
            av_log(c->fc, AV_LOG_WARNING, "CTTS invalid\n");
            av_freep(&sc->ctts_data);
            sc->ctts_count = 0;
            return 0;
        }

        if (duration < 0 && i+2<entries)
            sc->dts_shift = FFMAX(sc->dts_shift, -duration);
    }

    av_dlog(c->fc, "dts shift %d\n", sc->dts_shift);

    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.