A security related bug was discovered on certain HTC Android smartphones. This bug allowed any application that has access to the ACCESS_WIFI_STATE permission (something that the apps ask you before you install them) will let the application not only check on the status of your Wi-Fi but also have complete access to all your Wi-FI passwords. The handsets that are reported to have this bug include the Desire HD, T-Mobile myTouch 4G, Desire S, Sensation, EVO 3D, DROID Incredible, and the Thunderbolt 4G. However, HTC is now reporting that the problem has already been solved on certain devices, although which ones exactly was not mentioned.
GSM Arena, Wi-Fi security issue found on HTC devices