Western Digital My Cloud, My Cloud Mirror Gen2, My Cloud EX2 Ultra, My Cloud EX2100, My Cloud EX4100, My Cloud DL2100, My Cloud DL4100, My Cloud PR2100 and My Cloud PR4100 firmware before 2.31.174 is affected by an unauthenticated file upload vulnerability. The page web/jquery/uploader/uploadify.php can be accessed without any credentials, and allows uploading arbitrary files to any location on the attached storage.