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 ...

Exclusive: Site takes a cut of subscriptions to content that promotes far-right ideology, white supremacy and antisemitism ...

The move comes as Substack has been investing more heavily in video and livestreaming, as it looks to compete with platforms like YouTube and Patreon for both creators and viewers.