It has recently been found that WPA2 protocol is vulnerable to hacking. They are known as Krack Attacks (Key Reinstallation AttaCKS) and there is a website where you can learn more about it. It is found that Android and Linux are most vulnerable to this exploit. They can be tricked into reinstalling an encryption key with all 0s that will allow them to enter your network and then get to sites you visit and capture your login credentials.
If you watch the video below you will see it is a rather involved process to actually crack into the network but that doesn’t stop someone who is intent on getting into your network.
There isn’t a whole lot you can do because this vulnerability bypasses any security measures. Some of the more simple things you can do is not use unsecure Wi-Fi. Ever. Keep your firmware to your router updated. Do not downgrade to even more insecure protocols like WPA or WEP.