Mark Cuban-backed business filing service ZenBusiness leaked - 5 million customer records now public after ShinyHunters extortion failed

ZenBusiness customer data is now public on Have I Been Pwned, with 5,118,184 unique email addresses confirmed - alongside names, phone numbers, and CRM records pulled from Snowflake, Mixpanel, and Salesforce. ShinyHunters had threatened to publish the data in March after a failed extortion attempt; HIBP added the dataset yesterday. ZenBusiness is the AI-driven LLC formation and small business compliance platform backed by Mark Cuban. The breach extends the ShinyHunters wave that's already publicly released Pitney Bowes (8.2M), Carnival (7.5M), Udemy (1.4M), ADT (5.5M), and now ZenBusiness.

Check

If you used ZenBusiness to set up an LLC, treat any inbound communication referencing your real business name, formation date, or registered agent details as potentially hostile.

Affected

ZenBusiness customers - mostly small business owners, freelancers, and startup founders. The leak includes business formation details that uniquely identify the type of business you set up. Acute risk: small business owners targeted by 'compliance reminder' phishing referencing their real EIN, registered agent address, or annual report deadline.

Fix

Reset ZenBusiness account passwords and rotate any password reused on other accounts. Watch state filing systems for unauthorized changes to your registered agent or business address - attackers can hijack LLCs by changing these. Treat any 'urgent compliance notice' email as potentially hostile. For LLCs holding valuable assets, consider freezing changes through your secretary of state's office where supported.