The init_t38_info_conv function in epan/dissectors/packet-t38.c in the T.38 dissector in Wireshark 1.12.x before 1.12.9 does not ensure that a conversation exists, which allows remote attackers to cause a denial of service (application crash) via a crafted packet. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-8716