Mozilla security researcher moz_bug_r_a4 reported that through an interaction of frames and browser history it was possible to make the browser believe attacker-supplied content came from the location of a previous page in browser history. This allows for cross-site scripting (XSS) attacks by loading scripts from a misrepresented malicious site through relative locations and the potential access of stored credentials of a spoofed site.
In general these flaws cannot be exploited through email in the Thunderbird and SeaMonkey products because scripting is disabled, but are potentially a risk in browser or browser-like contexts in those products.
Vulmon