    def test_process_request__no_file(self, rf, caplog):
        request = rf.post("/", data={"file": "does_not_exist.txt", "s3file": "file"})
        S3FileMiddleware(lambda x: None)(request)
        assert not request.FILES.getlist("file")
        assert "File not found: does_not_exist.txt" in caplog.text
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.