function get_abs_item($dir, $item) {		// get absolute file+path
	return realpath(get_abs_dir($dir).DIRECTORY_SEPARATOR.$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.