A vulnerability, which was classified as critical, was found in MitraStar GPT-2541GNAC BR_g5.6_1.11(WVK.0)b26. Affected is an unknown function of the file /cgi-bin/settings-firewall.cgi of the component Firewall Settings Page. The manipulation of the argument SrcInterface leads to os command injection. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. We tried to contact the vendor early about the disclosure but the official mail address was not working properly.