Just to confirm, I've seen "new" blacole (av and c) reports now on two separate websites, including the McAfee user forum at https://community.mcafee.com/thread/47670
Detection of this only started with today's signatures.
I have visited both sites on machines running the Microsoft AV, and it's not giving either as having this infection, despite the fact that it is not new malware.
And on one, where I have access to the site content, I've done full scans with two more AVs without getting a report.
So unless McAfee can have malware on their own forum for at least six hours without noticing, I have to say that I rather suspect it's a false positive.
If it is, you need to get an update out fast, because the Telerik component is indeed used on a LOT of websites.
Mind, if Telerik have let out an infected release, they are the ones going to need a very rapid update, and a number of other AV companies need to get their acts together on detection.