Mozilla Firefox 1.x before 1.5.0.2 and 1.0.x before 1.0.8, Mozilla Suite before 1.7.13, and SeaMonkey before 1.0.1 allows remote attackers to read arbitrary files by (1) inserting the target filename into a text box, then turning that box into a file upload control, or (2) changing the type of the input control that is associated with an event handler.