PCWorld reports that Substack experienced a data breach in October 2025, exposing email addresses and phone numbers of approximately 697,000 users. The company discovered the security flaw on February ...

Newsletter platform Substack has confirmed it suffered a security incident, leading to the compromise of users’ email addresses and phone numbers. Chris Best, the CEO of Substack, notified users of ...

Newsletter platform Substack is notifying users of a data breach after attackers stole their email addresses and phone numbers in October 2025. Although the incident occurred four months ago, CEO ...