In Wireshark 2.6.0 to 2.6.1, 2.4.0 to 2.4.7, and 2.2.0 to 2.2.15, dissectors that support zlib decompression could crash. This was addressed in epan/tvbuff_zlib.c by rejecting negative lengths to avoid a buffer over-read. http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-14340