CVE-2018-19987: OS Command Injection

D-Link DIR-822 Rev.B 202KRb06, DIR-822 Rev.C 3.10B06, DIR-860L Rev.B 2.03.B03, DIR-868L Rev.B 2.05B02, DIR-880L Rev.A 1.20B0101i3seBETA, and DIR-890L Rev.A 1.21B02BETA devices mishandle IsAccessPoint in /HNAP1/SetAccessPointMode. In the SetAccessPointMode.php source code, the IsAccessPoint parameter is saved in the ShellPath script file without any regex checking. After the script file is executed, the command injection occurs. A vulnerable /HNAP1/SetAccessPointMode XML message could have shell metacharacters in the IsAccessPoint element such as the telnetd string.