On June 19th Opera Software, maker of the Opera browser discovered and recovered from a targeted attack on its internal network infrastructure. The attackers made off with at least one old and expired Opera code signing certificate, which they have used to sign some malware.
Users are strongly urged to update to the latest version of Opera as soon as it is available.
Read more here – http://my.opera.com/securitygroup/blog/2013/06/26/opera-infrastructure-attack