juniper_mlfr_print(netdissect_options *ndo,
                   const struct pcap_pkthdr *h, register const u_char *p)
{
        struct juniper_l2info_t l2info;

        l2info.pictype = DLT_JUNIPER_MLFR;
        if (juniper_parse_header(ndo, p, h, &l2info) == 0)
            return l2info.header_len;

        p+=l2info.header_len;

        /* suppress Bundle-ID if frame was captured on a child-link */
        if (ndo->ndo_eflag && EXTRACT_32BITS(l2info.cookie) != 1)
            ND_PRINT((ndo, "Bundle-ID %u, ", l2info.bundle));
        switch (l2info.proto) {
        case (LLC_UI):
        case (LLC_UI<<8):
            isoclns_print(ndo, p, l2info.length);
            break;
        case (LLC_UI<<8 | NLPID_Q933):
        case (LLC_UI<<8 | NLPID_IP):
        case (LLC_UI<<8 | NLPID_IP6):
            /* pass IP{4,6} to the OSI layer for proper link-layer printing */
            isoclns_print(ndo, p - 1, l2info.length + 1);
            break;
        default:
            ND_PRINT((ndo, "unknown protocol 0x%04x, length %u", l2info.proto, l2info.length));
        }

        return l2info.header_len;
}

The product reads data past the end, or before the beginning, of the intended buffer.