A quick glance online shows multiple reports of Diablo 3 accounts being hacked, suggesting it is a growing issue. Players have seen the loss of items stored in character inventory and stash, and gold removed as their accounts are stripped bare. Blizzard has been working to “roll back” affected characters to a point before accounts were compromised, but some progress is lost.
The reports coincided with the EU Diablo 3 servers going offline on Sunday afternoon for around four hours, preventing players from logging in (error 33). It has been suggested that the EU servers were taken offline following a SQL injection attack, but this remains unconfirmed.