Mozilla Firefox 3.x before 3.0.5 and 2.x before 2.0.0.19, Thunderbird 2.x before 2.0.0.19, and SeaMonkey 1.x before 1.1.14 allow remote attackers to bypass the same origin policy and access portions of data from another domain via a JavaScript URL that redirects to the target resource, which generates an error if the target data does not have JavaScript syntax, which can be accessed using the window.onerror DOM API.