Netis ADSL Router DL4322D firmware RTK 2.1.1 contains a buffer overflow vulnerability in the embedded FTP service that allows an authenticated remote user to trigger a denial of service. After logging in to the FTP service, sending an FTP command such as ABOR with an excessively long argument causes the service, and in practice the router, to crash or become unresponsive, resulting in a loss of availability for the device and connected users.