AT&T announced on Saturday it is investigating a data breach involving the personal information of more than 70 million current and former customers leaked on the dark web.

According to information about the breach on the company’s website, 7.6 million current account holders and 65.4 million former account holders have been impacted. An AT&T press release said the breach occurred about two weeks ago, and that the incident has not yet had a “material impact” on its operations.

AT&T said the information included in the compromised data set varies from person to person. It could include social security numbers, full names, email and mailing addresses, phone numbers, and dates of birth, as well as AT&T account numbers and passcodes.

The company has so far not identified the source of the leak, at least publicly.