Opera Software has gone public that its network was recently hacked. Hackers were able to steal at least one code-signing certificate, which they then used to sign malicious code. It is possible that a few thousand Windows users, who were using Opera between 01.00 and 01.36 UTC on June 19th, may automatically have received and installed the malicious software. To be on the safe side, we will roll out a new version of Opera which will use a new code signing certificate.”]
Source: https://grahamcluley.com/opera-hacked-code-signing-certificate-stolen-used-to-spread-malware/