[zokier]

It's only insecure if MS-CHAP is used for authentication, ie when used in WPA2-EAP mode. More commonly WPA2-PSK is used, which remains unaffected.

[ajross]

In English this means that if you're using the standard "share a single password for the wifi network" mode that all consumers understand, you're fine. If you're in an enterprisey environment where you use your own wifi password that is the same as your login password elsewhere, you're in trouble.

[kbolino]

You may be in trouble. There are other forms of EAP that do not use MS-CHAP, like EAP-TLS.

[helper]

WPA-Enterprise networks that use MS-CHAPv2 are generally tunneling it inside of another secure channel (such as TLS with PEAP). In those cases you are not at risk to over the air snooping.