Snort 1.6, when running in straight ASCII packet logging mode or IDS mode with straight decoded ASCII packet logging selected, allows remote attackers to cause a denial of service (crash) by sending non-IP protocols that Snort does not know about, as demonstrated by an nmap protocol scan.
Unknown vulnerability in IP defragmenter (frag2) in Snort before 1.8.3 allows attackers to cause a denial of service (crash).