In mozilla.general (Vulnerability discovered in Firefox extensions) user WaltS48 posted a link to this article at arstechnica.com, what summarizes results of research by some people at the Northeastern University. My summary of the summary: FF’s add-on concept eases attacks via add-ons. Or from add-on-developers’ point of view this concept might ease creation of great tools, but handicaps attempts to get them secure. The complete research report can be downloaded from here.
Of course SeaMonkey suffers from the same vulnerability via add-ons.
BTW something completely different: Not yet reviewed a SeaMonkey-Bug-Report today? May be you can have a look at this UNCONFIRMED one: Bug 1262754 – Copy table contents and paste to composer shows contents of most top left cell before Table. We need your help there!