The EU can suspend Hungary via Article 7, removing voting rights and regional funds, possible leading even to expulsion from the EU
However, member states and the EP are very wary of using this power and being seen to "interfere" in the internal politics of a member state
So, it is a slow process, with all parties giving Hungary chance after chance to change track
Poland and the UK in particular have been opposing the Article 7 process - so it may be easier after Brexit
The EU Commission started Article 7 proceedings in December 2017
and the EU Parliament voted in favour in September 2018:^
https://www.euronews.com/2018/09/12/european-parliament-votes-to-trigger-article-7-sanctions-procedure-against-hungary
The measure to trigger Article 7 sanctions proceduress^ garnered the necessary majority needed to pass, with 448 voting in favor of the motion, 197 against and 48 abstentions.
The move means that Hungarian Prime Minister Viktor Orban's government could eventually lose its EU voting rights.