A buffer overflow vulnerability was discovered in Tenda W20E router firmware version V15.11.0.6. The vulnerability exists in the addDhcpRule function where attackers can send overly long addDhcpRules data. The sscanf function processes this data without proper size validation, leading to buffer overflows in dhcpsIndex, dhcpsIP, and dhcpsMac variables. This could allow attackers to exploit the router's DHCP functionality to cause memory corruption.