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 ...

The company has emailed affected users after a dark web source claims the data of almost 700,000 users was compromised. Substack, a high-profile publishing platform widely used by academics, ...

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 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 ...

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 ...