The San Francisco-based company did not disclose how many MyTalk website accounts were affected, saying that the number was "limited" and that the attack was blocked within hours of hackers breaching its computer system.
"Based on our investigation to date, we do not believe there has been any unauthorized use of login information or unauthorized access to information in your account," Jawbone said in messages emailed to affected users.
Jawbone disabled access to accounts and called on people to reset passwords.
"Of course, just choosing a new password isn't enough," Graham Cluley of Sophos computer security firm said in a blog post about the hack.
"You should also ensure that the old password (the one that may now be in the hands of hackers) is not being used by you anywhere else on the internet."
If successful at decrypting stolen password data, hackers could try using it to get into other accounts associated with swiped email addresses, Cluley warned.
"That could be disastrous for if, for instance, you were using the same password on say your actual email account," the security blogger wrote.
A MyTalk website lets people customize Jawbone wireless earpieces and Jambox speakers with mini-applications or features such as personalized voice notifications.