The s7comm_decode_ud_cpu_szl_subfunc function in epan/dissectors/packet-s7comm_szl_ids.c in the S7COMM dissector in Wireshark 2.0.x before 2.0.1 does not validate the list count in an SZL response, which allows remote attackers to cause a denial of service (divide-by-zero error and application crash) via a crafted packet.