A little research shows two threads.
1) There have been similar alerts recently related to infected java applets and .js files infected with trojan.script.generic altogether.
2) Also loads of similar trojan.script.generic lead to ransomware (UKASH type), the latter being quite a pain in the rear to remove.
So I'd advise you to be cautious with these sites, do not override the security check unless you're certain your antivirus and browser settings offer thorough .js protection.
Hopefully we'll have more info in a couple of hours, as these blacklist additions generate webmaster notifications.
Links provided to recent (atm) Java security alerts and ukash remover, if ever.
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EDIT : After reviewing the incriminated sites I have found (one of) the way(s) infection proceeds.
Some of the provided videos are fake, consisting in an image mimicking an embedded video player (youtube for instance). The image is linked to a (supposedly malicious) .js hosted by chzb.gr, which is apparently (no thorough research there, but DNS records and website informer show coherent data) the legit fileserver for cheezburger items.
( chzb.gr is also referenced by google as malicious, btw. And beware, infected items also show on other sub-sites, spotted two on I Can Has recent additions.)
So when you click on that lolcat video it instead could download malicious software.
A hint to avoid this : Check the player lower controls (fullscreen and such) and if they're functional then go for it. If they're inert or status shows a link (Hovering over youtube's genuine player won't show a link) then step back.