If you've been to Sonic recently, you may want to go over your credit/debit card statement when possible. It has been reported that Sonic has been made aware of a breach affecting an unknown number of store payment systems.
Credit/Debit card numbers and info have already been found for sale in underground dark web stores (from the following states: Texas, North Carolina, Arkansas, Louisiana, Virginia, Georgia and Washington state) . This breach has been recently reported and is still under investigation to see how large of a breach it actually is.
CyberSec Industries advises that until more info is released, keep an eye out for any suspicious charges and report them immediately to your financial institution.
For more info on this breach, check out this great article by KrebsonSecurity: Breach at Sonic Drive-In May Have Impacted Millions of Credit, Debit Cards