MINNEAPOLIS (WCCO) — The personal data of thousands of Caribou Coffee customers was exposed in a recent security breach, according to the president of the Minnesota-based company.

The breach, which occurred for more than three months, involves 219 Minnesota stores, as well as dozens more in six other states.

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Caribou President John Butcher released a statement Thursday afternoon that said the company first contacted a cyber-security firm soon after noticing “unusual activity” on their network on Nov. 28. Two days later, the firm discovered the source of the breach and halted the unauthorized access.

(credit: CBS)

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Customers who visited these Caribou locations between Aug. 28 and Dec. 3 may have had their credit card numbers, expiration dates and security codes stolen. Butcher says customers who used their Caribou Coffee Perks or another loyalty account during those three months of exposure were not impacted.

Butcher says Caribou is strengthening their computer network to prevent future attacks, and the FBI is investigating the breach.

Customers are urged to look over credit and debit card statements for any irregularities. The company has also set up a customer hotline about the breach: 1-877-698-3760.

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The data breach also involved customers in Wisconsin, Iowa, Kansas, Colorado, Georgia and Florida.