Newsletter platform Substack reports data breach exposing user emails and phone numbers but not financial details
San Francisco: Substack said hackers got into their system and took some user information.
The company found out in February that someone got into their systems in October. The hackers got email addresses and phone numbers from user accounts. They also took some other internal information that Substack did not name.
Good news: credit card numbers and passwords were safe and not taken. The chief of Substack, Chris Best, sent an email to say sorry about what happened. He said they found the problem, fixed it, and are looking into what happened.
Substack did not say how many people were affected. They also did not say why it took five months to find out about the breach. The company said there is no proof the stolen information is being used badly, but they asked people to be careful about strange emails and texts.
Substack has more than 50 million subscriptions and over 5 million paid ones. The company got $100 million in money from investors in 2025 to help grow their business.