The isis_print function, as called by isoclns_print, in tcpdump 3.9.1 and earlier allows remote attackers to cause a denial of service (infinite loop) via a zero length, as demonstrated using a GRE packet.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10159
http://www.securityfocus.com/bid/13392
http://www.securityfocus.com/archive/1/430292/100/0/threaded
http://www.securityfocus.com/archive/1/396932
http://www.redhat.com/support/errata/RHSA-2005-421.html
http://www.redhat.com/support/errata/RHSA-2005-417.html