Ars Technica has a post about some recent news regarding over 7,500 unpatched routers:
“According to a report by Netlab 360’s Genshen Ye, more than 7,500 of them are actively being spied on by attackers, who are actively forwarding full captures of their network traffic to a number of remote servers.”
From earlier this year in May 2018:
You can use localrouter.net to find your local router’s web interface.
Before starting the firmware update on a router or modem (many ISPs control the firmware updates to modems) it is a good idea to back up the configuration settings incase things get reset etc. Firmware updates can also have bug fixes as well as security updates.