The Opera browser's built-in password manager has been compromised - specifically the sync system. While the attack was just discovered, it's unknown at this point when it started. It appears all Opera sync users are affected though, on any platform.
Although we only store encrypted (for synchronized passwords) or hashed and salted (for authentication) passwords in this system, we have reset all the Opera sync account passwords as a precaution.
OperaWe have also sent emails to all Opera sync users to inform them about the incident and ask them to change the password for their Opera sync accounts. In an abundance of caution, we have encouraged users to also reset any passwords to third party sites they may have synchronized with the service.