MadWifi, when Ad-Hoc mode is used, allows remote attackers to cause a denial of service (system crash) via unspecified vectors that lead to a kernel panic in the ieee80211_input function, related to "packets coming from a 'malicious' WinXP system."
ieee80211_input.c in MadWifi before 0.9.3 does not properly process Channel Switch Announcement Information Elements (CSA IEs), which allows remote attackers to cause a denial of service (loss of communication) via a Channel Switch Count less than or equal to one, triggering a channel change.