A hacker has broken into Jack Dorsey’s own Twitter account.

It’s not clear how it happened, but the hacker posted over a dozen tweets in quick succession, including racial slurs. Not only that, it means the unnamed hacker also has access to the Twitter chief executive’s private direct messages.

One of the tweets posted a Twitter handle for someone who purported to take credit for the account takeover. That account was quickly suspended.

Dorsey has over 4.21 million followers.

Twitter allows users to secure their accounts with two-factor authentication. Facebook boss Mark Zuckerberg once had his Twitter account hacked because his account didn’t use the secondary security feature. He also had a ridiculously easy-to-guess password.

It’s not known how Dorsey’s account was hacked. Often the cause is a password reuse attack, where hackers take breached usernames and passwords from one website and run them against another site. Accounts who share passwords from site to site are more likely to get hacked.

We’ve reached out to Twitter for more but did not immediately hear back.