Sicurezza: Opera.com craccato, rischio malware per utilizzatori Opera su windows

What Opera is describing here is the nightmare of any company having millions of users:- Internal network breached- Signing certificates stolen- Certificates used to sign malware

Can it go worse?

Yes, it can.- the website distributed automatically company signed malware to their users:

Opera.com hacked, distributed malware signed with their certificate to probably thousand of users (Update) | Avira ? TechBlog