US telecommunications giant T-Mobile has disclosed that the personal data of its employees and customers has been hacked. This is the second security breach T-Mobile has admitted in the last six months, after the first incident was reported last November.

"Our cybersecurity team recently identified and shut down a malicious attack against our email vendor that led to unauthorized access to certain T-Mobile employee email accounts, some of which contained account information for T-Mobile customers and employees," the company said in a statement.

It launched an investigation with assistance from leading cybersecurity forensics experts.

"The information accessed may have included customer names and addresses, phone numbers, account numbers, rate plans, and features, and billing information. Your financial information (including credit card information) and Social Security number were not impacted," said T-Mobile.

The company is sending out SMS notifications to all impacted users.

T-Mobile in November 2019 had revealed that there was an incident in which a malicious party was able to access account information of some of its prepaid customers.

The company's cybersecurity team discovered and shut down the data breach and that it has reported the incident to the authorities.

The leaked data included details such as customer names, billing addresses, phone numbers, account numbers, rate plans, and plan features.

Another US carrier Sprint recently admitted hackers accessed some of its user data via the Samsung official website.