In Wireshark 2.6.0, 2.4.0 to 2.4.6, and 2.2.0 to 2.2.14, the Q.931 dissector could crash. This was addressed in epan/dissectors/packet-q931.c by avoiding a use-after-free after a malformed packet prevented certain cleanup. https://nvd.nist.gov/vuln/detail/CVE-2018-11358