Mozilla developer Boris Zbarsky reported an inconsistency
with the different JavaScript engines in how JavaScript native getters on
window objects are handled by these engines. This inconsistency can
lead to different behaviors in JavaScript code, allowing for a potential
security issue with window handling by bypassing of some security checks.
In general this flaw cannot be exploited through email in the Thunderbird and Seamonkey products because scripting is disabled in mail, but is potentially a risk in browser or browser-like contexts.
Vulmon