Restaurant chain Jimmy John’s warns of potential hacking by Reuters @FortuneMagazine September 24, 2014, 6:37 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Sandwich restaurant chain Jimmy John’s said there was a potential security breach involving customers’ credit and debit card data at 216 of its stores and franchised locations on July 30. An intruder stole log-in credentials from the company’s vendor and used the credentials to remotely access the point-of-sale systems at some corporate and franchised locations between June 16 and Sept. 5, the company said. The chain is the latest victim in a series of security breaches among retailers such as Target Corp TGT , Michaels Stores MIK and Neiman Marcus. Home Depot HD said last week some 56 million payment cards were likely compromised in a cyberattack at its stores, suggesting the hacking attack at the home improvement chain was larger than the breach at Target Corp. More than 12 of the affected Jimmy John’s stores are in Chicago area, according to a list disclosed by the company. The breach has been contained and customers can use their cards at its stores, the privately held company said. Jimmy John’s said it has hired forensic experts to assist with its investigation. “Cards impacted by this event appear to be those swiped at the stores, and did not include those cards entered manually or online,” Jimmy John’s said on Wednesday. The Champaign, Illinois-based company said stolen information may include the card number and in some cases the cardholder’s name, verification code, and/or the card’s expiration date.