Dlink Dir-3040us A1 1.20b03a hotfix is vulnerable to Buffer Overflow. Any user having read/write access to ftp server can write directly to ram causing buffer overflow if file or files uploaded are greater than available ram. Ftp server allows change of directory to root which is one level up than root of usb flash directory. During upload ram is getting filled and causing system resource exhaustion (no free memory) which causes system to crash and reboot.