Twitch has reset passwords and stream keys, requiring users to create new ones, after discovering "there may have been unauthorized access to some Twitch user account information," the service announced today.
"We also recommend that you change your password at any website where you use the same or a similar password," Twitch said in this bulletin.
Users who were directly affected by the breach will be contacted with additional details.
A Twitch spokesman declined further comment.
Update: GamesBeat got a copy of the email Twitch sent to accounts it believes were compromised by the attack. The email warns that the user's email address, password, "limited credit card information," the most recent IP address used to access Twitch, and certain biographical details, if provided, were exposed.
"While we store passwords in a cryptographically protected form, we believe it's possible that your password could have been captured in clear text by malicious code when you logged into our site on March 3," Twitch told the users.