static int pcnet_tdte_poll(PCNetState *s)
{
    s->csr[34] = s->csr[35] = 0;
    if (s->tdra) {
        hwaddr cxda = s->tdra +
            (CSR_XMTRL(s) - CSR_XMTRC(s)) *
            (BCR_SWSTYLE(s) ? 16 : 8);
        int bad = 0;
        CHECK_TMD(cxda, bad);
        if (!bad) {
            if (CSR_CXDA(s) != cxda) {
                s->csr[60] = s->csr[34];
                s->csr[61] = s->csr[35];
                s->csr[62] = CSR_CXBC(s);
                s->csr[63] = CSR_CXST(s);
            }
            s->csr[34] = cxda & 0xffff;
            s->csr[35] = cxda >> 16;
#ifdef PCNET_DEBUG_X
            printf("pcnet: BAD TMD XDA=0x%08x\n", cxda);
#endif
        }
    }

    if (CSR_CXDA(s)) {
        struct pcnet_TMD tmd;

        TMDLOAD(&tmd, PHYSADDR(s,CSR_CXDA(s)));

        CSR_CXBC(s) = GET_FIELD(tmd.length, TMDL, BCNT);
        CSR_CXST(s) = tmd.status;
    } else {
        CSR_CXBC(s) = CSR_CXST(s) = 0;
    }

    return !!(CSR_CXST(s) & 0x8000);
}

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.