Newsletter platform Substack has confirmed a data breach in an email to users. The company said that in October, an “unauthorized third party” accessed user data, including email addresses, phone numbers, and other unspecified “internal metadata.” Substack specified that more sensitive data, such as credit card numbers, passwords, and other financial information, was unaffected. In an email sent to users, Substack chief executive Chris Best said that the company identified the issue in February