Hungary may be a "small" country, but Austrian banks have a lot of exposure to Hungarian sovereign debt and Hungarian businesses and real estate. Austrian banks exposure to sov. debt of Romania and Hungary is about $80 Billion, more than French bank’s exposure to Greek sovereign debt at about $78 Billion. 

Greek exposure to Romanian debt and Bulgarian debt is about $40 Billion.  Half of Austrian bank exposure to Romania and Hungary. 

Hungary and the much larger Ukraine, are already operating under austerity programs with loans from the IMF.

Just as the likelihood of catching a virus increases with the number of people you shake hands with at a function, so too does the risk of contagion rise with more exposures to debt repayment problems. Hungary has been "taking the medicine" for 18 months already and not only isn't "cured", it is still contagious to others.