Opera users who utilized the browser's cloud sync option may have had that synchronized data taken by hackers, according to the company. While the full extent of the breach isn't yet known, Opera fears that passwords saved in the browser's manager may have been exposed.

Opera's disclosure is light on details at this point, saying they "detected signs of an attack" that indicated somebody had gained access to the servers used for their synchronization service. They say it was "quickly blocked," but also can't say with certainty what—if anything—was compromised.

Most concerning is the possibility is that the synced passwords kept on the server were taken along with usernames and account passwords.

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