CNN: Target Shoppers Vulnerable to Credit Card Fraud

Target: 40 Million Credit Cards Compromised (CNN Money)

A breach of credit and debit card data at discount retailer Target may have affected as many as 40 million shoppers who went to the store in the three weeks after Thanksgiving, the retailer said Thursday.

Late Wednesday, the Secret Service, which is charged with safeguarding the nation's financial infrastructure and payment systems, confirmed it was investigating the breach. Spokesman Brian Leary declined further comment.

The breach first came to light via a report from respected security researcher Brian Krebs, who said Target had suffered a data breach around the time of Black Friday last month "potentially involving millions of customer credit and debit card records."