I think there are a couple of old mosques in Hungary, not modern structures, where worship is still allowed, such as the Mosque of Jakovali Hassan Pasha in Pecs. But I’d be happy to be proved wrong.
Poland and Hungary have small Tatar Muslim minorities who have lived there for several centuries. Charles Bronson’s father came from a Polish Tatar background, although he was raised as a Christian. That ancestry explains his somewhat Asiatic appearance. The Polish Tatars have been loyal to their nation, and I suppose the same is true of their Hungarian kinsmen.