function get_is_file($dir, $item) {		// can this file be edited?
	return @is_file(get_abs_item($dir,$item));
}
The software 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 software 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.