Some telnet clients allow remote telnet servers to request environment variables from the client that may contain sensitive information, or remote web servers to obtain the information via a telnet: URL.

WinU 1.0 through 5.1 has a backdoor password that allows remote attackers to gain access to its administrative interface and modify configuration.

WinU 5.x and earlier uses weak encryption to store its configuration password, which allows local users to decrypt the password and gain privileges.