AT&T: Data breach affects 73 million or 51 million customers. No, we won’t explain.

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AT&T is notifying millions of current or former customers that their account data has been compromised and published last month on the dark web. Just how many millions, the company isn't saying.

In a mandatory filing with the Maine Attorney General’s office, the telecommunications company said 51.2 million account holders were affected. On its corporate website, AT&T put the number at 73 million. In either event, compromised data included one or more of the following: full names, email addresses, mailing addresses, phone numbers, social security numbers, dates of birth, AT&T account numbers, and AT&T passcodes. Personal financial information and call history didn’t appear to be included, AT&T said, and data appeared to be from June 2019 or earlier.

The disclosure on the AT&T site said the 73 million affected customers comprised 7.6 million current customers and 65.4 million former customers. The notification said AT&T has reset the account PINs of all current customers and is notifying current and former customers by mail. AT&T representatives haven’t explained why the letter filed with the Maine AG lists 51.2 million affected and the disclosure on its site lists 73 million.