Western Digital My Cloud Cloud, Mirror Gen2, EX2 Ultra, EX2100, EX4100, DL2100, DL4100, PR2100 and PR4100 before firmware 2.31.183 are affected by a code execution (as root, starting from a low-privilege user session) vulnerability. The cgi-bin/webfile_mgr.cgi file allows arbitrary file write by abusing symlinks. Specifically, this occurs by uploading a tar archive that contains a symbolic link, then uploading another archive that writes a file to the link using the "cgi_untar" command. Other commands might also be susceptible. Code can be executed because the "name" parameter passed to the cgi_unzip command is not sanitized.

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 authentication bypass vulnerability. The login_mgr.cgi file checks credentials against /etc/shadow. However, the "nobody" account (which can be used to access the control panel API as a low-privilege logged-in user) has a default empty password, allowing an attacker to modify the My Cloud EX2 Ultra web page source code and obtain access to the My Cloud as a non-Admin My Cloud device user.