static int asf_read_subpayload(AVFormatContext *s, AVPacket *pkt, int is_header)
{
    ASFContext *asf = s->priv_data;
    AVIOContext *pb = s->pb;
    uint8_t sub_len;
    int ret, i;

    if (is_header) {
        asf->dts_delta = avio_r8(pb);
        if (asf->nb_mult_left) {
            asf->mult_sub_len = avio_rl16(pb); // total
        }
        asf->sub_header_offset = avio_tell(pb);
        asf->nb_sub = 0;
        asf->sub_left = 1;
    }
    sub_len = avio_r8(pb);
    if ((ret = av_get_packet(pb, pkt, sub_len)) < 0) // each subpayload is entire frame
        return ret;
    for (i = 0; i < asf->nb_streams; i++) {
        if (asf->stream_index == asf->asf_st[i]->stream_index) {
            pkt->stream_index  = asf->asf_st[i]->index;
            break;
        }
    }
    asf->return_subpayload = 1;
    if (!sub_len)
        asf->return_subpayload = 0;

    if (sub_len)
        asf->nb_sub++;
    pkt->dts = asf->sub_dts + (asf->nb_sub - 1) * asf->dts_delta - asf->preroll;
    if (asf->nb_mult_left && (avio_tell(pb) >=
                              (asf->sub_header_offset + asf->mult_sub_len))) {
        asf->sub_left = 0;
        asf->nb_mult_left--;
    }
    if (avio_tell(pb) >= asf->packet_offset + asf->packet_size - asf->pad_len) {
        asf->sub_left = 0;
        if (!asf->nb_mult_left) {
            avio_skip(pb, asf->pad_len);
            if (avio_tell(pb) != asf->packet_offset + asf->packet_size) {
                if (!asf->packet_size)
                    return AVERROR_INVALIDDATA;
                av_log(s, AV_LOG_WARNING,
                       "Position %"PRId64" wrong, should be %"PRId64"\n",
                       avio_tell(pb), asf->packet_offset + asf->packet_size);
                avio_seek(pb, asf->packet_offset + asf->packet_size, SEEK_SET);
            }
        }
    }

    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.