We’ve all got a router to connect to the web, and like everything else connected to the internet, routers can be hacked. Someone can therefore not only get access to your entire home system – laptops, phones, TV etc. - but they can also use that hardware, in your own house, to attack people on the other side of the planet. This article from security for WordPress people, Wordfence, discusses the issues and tells you how to check to see if your own router is currently safe.
For more details see https://www.wordfence.com/blog/2017/04/check-your-router/?utm_source=list&utm_medium=email&utm_campaign=041217.