The hacker was able to access to see other users' email addresses, change their passwords, remove two-factor authentication from their accounts, ban users and more, reports the Vice.
The hacker shared screenshots of the personal information of some of Roblox's most high-profile users including YouTuber Linkmon99.
According to the hacker, he changed the password for two accounts and sold their items.
Based on the screenshots of the customer support panel, the hacker was also able to reset passwords and change other user data as well.
Meanwhile, Roblox has addressed the issue and individually notified the "small number of users who were impacted".
The company has reported the hacker's actions to the bug bounty platform HackerOne as an additional measure.
Roblox is available across PC and Xbox platforms, and is especially popular with young gamers.