AT&T has announced that it is currently investigating a massive data leak that has exposed the personal information of 73 million current and former customers. The telecommunications giant stated that the data, which includes Social Security numbers, was discovered on the "dark web" approximately two weeks ago. The leaked information, dating back to 2019 or earlier, does not include financial details or call history.

The compromised data affects approximately 7.6 million current AT&T account holders and 65.4 million former account holders. AT&T has already taken steps to reset the passcodes of current users and is in the process of notifying customers whose sensitive personal information has been exposed. The company is also advising customers to remain vigilant about any changes to their accounts or credit reports and will be offering credit monitoring services where applicable.

Cybersecurity researcher Troy Hunt noted that this recent data leak closely resembles a similar breach that surfaced in 2021, which AT&T did not acknowledge. If the company failed to notify impacted customers in a timely manner, it could potentially face class action lawsuits. AT&T has not yet confirmed if the leaked data originated from their systems or from one of their vendors.

This latest incident adds to the list of challenges faced by AT&T this year, including a cellphone service outage in February that was attributed to a technical coding error. The company has not provided further details on the ongoing investigation into the source of the data leak.