A stack-based buffer overflow in the LAN UPnP service running on UDP port 1900 of Swisscom Internet-Box (2, Standard, and Plus) prior to v09.04.00 and Internet-Box light prior to v08.05.02 allows remote code execution. No authentication is required to exploit this vulnerability. Sending a simple UDP packet to port 1900 allows an attacker to execute code on a remote device. However, this is only possible if the attacker is inside the LAN. Because of ASLR, the success rate is not 100% and leads instead to a DoS of the UPnP service. The remaining functionality of the Internet Box is not affected. A reboot of the Internet Box is necessary to attempt the exploit again.