Vulnerability Instance

Mozilla developer Masayuki Nakano discovered that the
NativeKey widget continues handling key messages even when it is
destroyed by dispatched event listeners. This could result in some key events
being applied to other objects or plugins if the widget memory is reallocated to
them, leading to a non-exploitable crash. 
In general this flaw cannot be exploited through email in the
Thunderbird product because scripting is disabled, but is potentially a risk in
browser or browser-like contexts.