The carrier said three per cent of its customers were affected, or about two million to 2.5 million of its 77 million customers.
"On August 20, our cyber-security team discovered and shut down an unauthorised access to certain information, including yours, and we promptly reported it to authorities. None of your financial data (including credit card information) or social security numbers were involved, and no passwords were compromised," the company said in a statement on Friday.
"However, some personal information may have been exposed, which may have included one or more of the following: name, billing zip code, phone number, email address, account number and account type (prepaid or postpaid)," it added.
All affected customers have been, or shortly will be, notified, said the company.
It is unclear whether the exposed data was actually stolen by the hackers.
Meanwhile, a T-Mobile representative informed that "encrypted passwords" had been exposed to hackers.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
