Directory traversal vulnerability in Mozilla Firefox before 2.0.0.4 on Windows allows remote attackers to read arbitrary files via ..%5C (dot dot encoded backslash) sequences in a resource:// URI.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.