Notably, all the affected videos came from Vevo accounts on YouTube. We've asked both Google and Vevo for comment. Despite the scripting claim, it's possible that this involved YouTube account breaches instead of a vulnerability inherent to YouTube itself. Whatever the cause, it's worrisome -- even if repairing the damage is easy, it shouldn't be that trivial for someone to alter numerous videos. The next incident may be less of a prank (as this appears to be) and more of a malicious campaign.

Update 4/10/18 10:45 AM ET: Vevo has confirmed to Engadget that a "security breach" affected a number of videos, and that it's continuing to look into the cause. You can read the full statement below.