A US telecom giant revealed that personal data belonging to 73 million current or former customers of the US telecoms company AT&T has been leaked online.
The company said information, including addresses, social security numbers, and passcodes, was published on the dark web.
AT&T said it had not identified evidence indicating the data had been stolen but had brought in cybersecurity experts to investigate.
The company said it had reset customers’ passcodes.
The company urged them to “remain vigilant by monitoring account activity and credit reports.”
The data involved in the breach appears to be from 2019 or earlier and is linked to 7.6 million customers and 65.4 million former account holders.
It also includes information such as full names, email addresses, and dates of birth, though AT&T said financial information did not appear in the leak.
The company stated that it was unclear whether the data had originated from its own systems or via a third-party supplier.
AT&T’s wireless 5G network covers around 290 million people across the US and is one of the country’s largest mobile and internet services providers.
In February, a major outage affected tens of thousands of phone users, prompting the firm to apologize and offer a $5 credit to those affected.
Prosecutors in New York investigated that episode, which left people unable to use their phones for around 12 hours.
