Wireless LANs (WLAN) are becoming ubiquitous, as more and more consumer electronic equipments start to support them. This creates new security concerns, since hackers no longer need physical connection to the networks linking the devices, but only need to be in their proximity, to send malicious data to exploit some vulnerability. In this paper we present a fuzzer, called Wdev-Fuzzer, which can be utilized to locate security vulnerabilities in Wi-Fi device drivers. Our preliminary experiments with a Windows Mobile 5 device driver indicate that Wdev-Fuzzer can be quite effective at finding previously unknown problems.