(CBS) — The restaurant chain Jimmy John’s may be the latest victim of security breach of customer data, the chain announced Wednesday in a press release.

Jimmy John’s says approximately 216 stores have been affected and that data from debit and credit cards that were swiped at the stores from have been compromised. The chain says that card info entered online or manually remains secure.

Stolen data may include the cardholder’s name, verification code and the card’s expiration date.The Illinois based-chain hired forensic investigators on July 30 to investigate a possible breach and came to the conclusion that log-in credentials from the point-of-sale systems was compromised.

Jimmy John’s says the breach has been contained and that stricter security measures are being implemented to prevent future data breaches.

23 stores in Illinois were affected by the possible breach, including four in Chicago. To find the full list of locations that may have been affected by the breach, click here.