America’s Favorite Drive-In has been affected. Krebs On Security has confirmed with Sonic that a breach has affected 5 million credit and debit cards.

Sonic discovered the breach last week after learning that there had been unusual activity within its credit card processing.

From Sonic:

We are working to understand the nature and scope of this issue, as we know how important this is to our guests. We immediately engaged third-party forensic experts and law enforcement when we heard from our processor. While law enforcement limits the information we can share, we will communicate additional information as we are able.

Since Sonic has over 3,400 stores in 45 states, there is no way to know which locations were affected.

Like always, keep an eye on your credit card/debit card statements. Should you see anything funny, please contact your card issuer immediately.