Firefox .url Shortcut File Information Disclosure

Mozilla Firefox 3.0.1 through 3.0.3, Firefox 2.x before 2.0.0.18, and SeaMonkey 1.x before 1.1.13, when running on Windows, do not properly identify the context of Windows .url shortcut files, which allows user-assisted remote attackers to bypass the Same Origin Policy and obtain sensitive information via an HTML document that is directly accessible through a filesystem, as demonstrated by documents in (1) local folders, (2) Windows share folders, and (3) RAR archives, and as demonstrated by IFRAMEs referencing shortcuts that point to (a) about:cache?device=memory and (b) about:cache?device=disk, a variant of CVE-2008-2810.