Substack said that customer data was accessed in October 2025, but wasn't discovered until early February.

Substack won't share official numbers, but it seems like a pretty significant data breach.

Substack, the hugely popular online content platform with 50 million active subscribers, has confirmed it has been hacked.

Lynch Carpenter is a national class action law firm with offices in Pennsylvania, California, and Illinois. Our firm has represented millions of clients in data privacy matters for more than a decade ...

The hacker claims to have stolen nearly 700,000 Substack user records, including email addresses and phone numbers.

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 ...