The Opera Sync service may have been compromised, according to a security notice released by Opera for its users.
Opera made every Sync user who received notice by mail of questionable activity with their accounts change their passwords in reaction to the purported incident.
However, some information was discovered to have been accessed, including login names and passwords for some sync users.
Opera made it clear that the system's authentication passwords are salted and hashed using per-user salts; yet, the business withheld details regarding the authentication passwords' hashing procedure.
Source: https://securityaffairs.com/50690/data-breach/opera-sync-security-breach.html
"id": "OPE2132291023",
"linkid": "opera-software",
"type": "Breach",
"date": "08/2016",
"severity": "60",
"impact": "3",
"explanation": "Attack with significant impact with internal employee data leaks"