send_pac_p(krb5_context context, KDC_REQ *req)
{
    krb5_error_code ret;
    PA_PAC_REQUEST pacreq;
    const PA_DATA *pa;
    int i = 0;

    pa = _kdc_find_padata(req, &i, KRB5_PADATA_PA_PAC_REQUEST);
    if (pa == NULL)
	return TRUE;

    ret = decode_PA_PAC_REQUEST(pa->padata_value.data,
				pa->padata_value.length,
				&pacreq,
				NULL);
    if (ret)
	return TRUE;
    i = pacreq.include_pac;
    free_PA_PAC_REQUEST(&pacreq);
    if (i == 0)
	return FALSE;
    return TRUE;
}

The product dereferences a pointer that it expects to be valid but is NULL.