All of the newsletter platforms have confirmed the data breach in an email to users. In October, an “unauthorized third party” accessed user data, including email addresses, phone numbers, and other unspecified “internal metadata,” the company said.

Subsec clarified that more sensitive data, such as credit card numbers, passwords and other financial information, was not affected.

In an email to customers, Subsac Chief Executive Chris Best said the company identified the issue in February that could have allowed someone to gain access to its systems. Best said the company has determined the problem and has launched an investigation.

“I’m reaching out to inform you of a security incident that resulted in the email address and phone number from your subsec account being shared without your permission,” Best said in an email to customers. “I’m incredibly sorry that this happened. We take our responsibility to protect your data and your privacy seriously, and we came up short here.”

It is unclear what exactly was the problem with his system, and the extent of the data that was accessed. It’s also not yet known why it took five months for the company to discover the breach, or if the company was contacted by hackers demanding a ransom. TechCrunch asked the company for more details, and we’ll update our story if we hear back.

Subsec did not say how many customers are affected. The company said it had no evidence that customer data was being misused, but did not say what technically meant, such as logs, it would have to detect evidence of abuse. However, the company asked users to be careful with emails and texts without specific hints or instructions.

On its website, Sibsk says its site has more than 50 million active subscriptions, including 5 million paid subscriptions. A milestone It arrived last March. In July 2025, the company raised $100 million in Series C funding led by Bond and Chernin Group (TCG), with participation from A16Z, Clutch Sports Group CEO Rich Paul, and Schemes co-founder Jens Gerd.