There has been a massive theft of about 40 million credit and debit card accounts used at retail giant Target between November 27 - December 15. The breach reportedly involved almost all of Target's 1,797 stores in the U.S. If you shopped at Target within the last 3 or 4 weeks, here's what you need to do:

There has been widespread unauthorized access to Target payment card data. If you shopped at Target between November 27, 2013 - December 15, 2013, you need to take some steps to protect yourself against potential misuse of your credit or debit information.

The first thing you need to do is check your debit/credit card statement. If you see charges that you or anyone with access to your card didn't make, call your bank immediately to alert them of the fraudulent charges. You can also contact the Federal Trade Commission (FTC) to report identity theft. Check out the FTC's website for more info. Target has issued this important notice with further information.