    def testPathTraverse(self):
        # need to perform this test with a "real" folder
        from OFS.Folder import Folder
        f = self.folder
        self.folder = Folder()
        self.folder.t, self.folder.laf = f.t, f.laf
        self.folder.laf.write('ok')
        self.assert_expected(self.folder.t, 'CheckPathTraverse.html')
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.