What is UPnP? Yes, it's still dangerous in 2021
UPnP (Universal Plug and Play) is a service that allows devices on the same local network to discover each other and automatically connect through standard networking protocols (such as TCP/IP HTTP, and DHCP). Some examples of UPnP devices are printers, gaming consoles, WiFi devices, IP cameras, routers, mobile devices, and Smart TVs. UPnP can also modify router settings to open ports into a firewall to facilitate the connection of devices outside of a network.