CVE-2012-1593 on Ubuntu 12.04 LTS (precise) - negligible.
Description:
epan/dissectors/packet-ansi_a.c in the ANSI A dissector in Wireshark 1.4.x before 1.4.12 and 1.6.x before 1.6.6 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a malformed packet.