The forums for DayZ have been hacked, resulting in members' usernames, emails and passwords being leaked.
The good news is that the passwords were not stored in plain text, but the company still strongly encourages its forum members to change their password.
The hack also brought down Mini DayZ, the free html5-based web version of the game, though the studio said in a Twitter update that it will "try to have @Mini_DayZ back up ASAP."
Bohemia also has plans to replace the IPBoards login system in the next two weeks, which should dramatically improve security. The forums will remain offline until then.
Here's the email Bohemia has been passing around (via Reddit:)
A security incident occurred on forums.dayzgame.com recently. According to our investigation all usernames, emails and passwords from forums.dayzgame.com were accessed and downloaded by hackers.
While the passwords were not stored in plain text, but in a more secure form, it is highly recommended that if you have used the same password elsewhere you change it immediately on all applicable websites and services.
We would like to apologise for the inconvenience caused, and share with you one of the major changes planned in order to mitigate similar risks in the future. We will be replacing the IPBoards login system with Bohemia Account within the next two weeks. As Bohemia Account is a separate custom-built service currently used by Bohemia Interactive Forums and Store, it offers much better security and its use should prevent similar incidents going forward.
We ask for your patience over the next few days and weeks as we implement this and other security overhauls, as there are likely to be service interruptions and forum unavailability from time to time. In particular, the forums will be down until migration to the Bohemia Account is complete. We will keep you up to date on vital info and scheduled down-time on the site itself and via our Twitter.