A T-Mobile mistake during an overnight technology update resulted in some customers seeing the private information of other users today. T-Mobile users posting on social media said they saw other customers’ billing details instead of their own during the incident that reportedly lasted for three hours or so this morning.

When contacted by Ars today, T-Mobile confirmed the problem and said it was caused by a faulty update. “There was no cyberattack or breach at T-Mobile,” a company spokesperson said. “This was a temporary system glitch related to a planned overnight technology update involving limited account information for fewer than 100 customers, which was quickly resolved.”

As The Verge wrote, T-Mobile customers “reported that they’re able to see other users’ account data—including their current credit balance, purchase history, credit card information, and home address—when signing into their own T-Mobile accounts.”

A subreddit dedicated to discussing T-Mobile set up a megathread for discussions on the matter. “I got not one but two people’s info when accessing my account through the app last night. Seemingly back to normal when I checked this morning,” one person wrote.

Fierce Wireless spoke to a T-Mobile user who saw other people’s private information. “A source told Fierce Wireless that when he logged into his T-Mobile account, he saw other people’s names, lines, billing history, addresses, call logs, and saved payment methods,” the news site reported.

T-Mobile users have reason to worry

Today’s data leak appears to be a minor problem compared to T-Mobile’s history of data breaches. In addition to breaches earlier this year, T-Mobile admitted in 2021 that attackers stole personal information on nearly 49 million accounts.

But even though today’s problem seems to have been small and fixed quickly, it’s another reason for cell phone users to be wary of T-Mobile’s ability to safeguard personal information.

In the Reddit thread, users expressed concern about their data and pointed out that T-Mobile now requires a debit card or linked bank account to set up automatic payments and receive the company’s AutoPay discount. T-Mobile stopped accepting credit cards for automatic payments a few months ago.

“And they want me to attach my banking information to get Auto Pay. It’ll never happen,” one person wrote.

https://arstechnica.com/?p=1969887