Mozilla Firefox before 1.8.0.13 and 1.8.1.x before 1.8.1.5 does not perform a security zone check when processing a wyciwyg URI, which allows remote attackers to obtain sensitive information, poison the browser cache, and possibly enable further attack vectors via (1) HTTP 302 redirect controls, (2) XMLHttpRequest, or (3) view-source URIs.
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.