Anyone who bought a house in the last 5 years with a mortgage is...

Anyone who bought a house in the last 5 years with a mortgage is toast. Back when they AUD was between $1 - 80c to the USD, house prices were lunacy in international terms. Now it's fallen to 60c it's about the same value as the US was during the 2006 bubble. Either the AUD falls to 45c or housing corrects down 30%. Probably both.

Remember CBA borrows a lot of its finance from overseas and before anyone says, "but they hedge!", please realise that each new dollar borrowed is at the currently existing exchange rate. Hedging doesn't mean they lock in all the money they borrow at some previous price. So the banks are getting money for 40% less value than they did before and given problems in the repo market, they might not be getting the money at all.