It indicates a possible exploit of an Integer Overflow vulnerability in the iSNS dissector for Ethereal/Wireshark.
A remote attacker could cause Ethereal to crash via a specially crafted packet.
Ethereal 0.10.3 - 0.10.4
Denial of Service: Remote attackers can crash vulnerable systems.
Upgrade to the latest version of Ethereal (now known as Wireshark):