Array index error in the (1) ieee80211_ioctl_getwmmparams and (2) ieee80211_ioctl_setwmmparams functions in net80211/ieee80211_wireless.c in MadWifi before 0.9.3.1 allows local users to cause a denial of service (system crash), possibly obtain kernel memory contents, and possibly execute arbitrary code via a large negative array index value.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.