The screenshot someone provided indicates that it is using heuristics and is detecting something on the html page. This is extremely general and heuristics are more prone to false alarms by the way they work. The people getting this should look around in their anti-malware utilities to see if there is a way for it to give you more information.
I presume the people getting this popup actually have antivir installed and that it is a real alert. Does anyone else see it with other anti-malware utilities?
I wouldn't freak out over this too much until more information is known. There is a high chance of nothing more than a false positive. Anyone who gets the message should reboot in safe mode and run fullscans with multiple updated anti-malware utilities (such as malwarebytes anti-malware). Please note anything that it says you have and report it here or somewhere because it will help in figuring this out.
