Blizzard has confirmed that Battle.net was subject to a security breach and some gamers' email addresses and security questions have been accessed.
The good news is that Blizzard has found "no evidence" to suggest that credit card details and other financial information was stolen.
Only the firm's China-based accounts are definitely safe and sound, with the North American servers the most affected.
Another password change
In a statement, the developer explained, "We use Secure Remote Password protocol (SRP) to protect these passwords, which is designed to make it extremely difficult to extract the actual password, and also means that each password would have to be deciphered individually."
Reassuring, but it doesn't mean you shouldn't change your passwords to be on the safe side, as per Blizzard's now all-too-familiar addendum:
"As a precaution, however, we recommend that players on North American servers change their password.
"Moreover, if you have used the same or similar passwords for other purposes, you may want to consider changing those passwords as well," it concluded.