If you or your child plays Fortnite, you might want to take a closer look at your recent credit card statements. Epic Games, the maker of the hit online battle royal title, admitted Wednesday that a flaw in the game’s log-in system could have allowed hackers to impersonate real players and purchase in-game currency using the credit cards on file. It’s unclear how many players may have been directly affected by the bug; Epic declined to comment on the scope of the vulnerability and said the matter has been addressed.