The breach which is said to have taken place last week was limited to moderation panels, their reports queue, and some tables in their backend database.
4Chan says the primary target of this security breach is their moderator account names and login credentials. Hackers also managed to access pass credentials of three 4Chan pass users.
4Chan said it doesn't process any payment information, all of them are being processed by Stripe. So, there is no financial data involved in this breach.
The vulnerability responsible for the data breach has reportedly been patched, after 4chan became aware of it.