HighwayGlider, on 25 February 2013 - 09:14, said:
I don't have an account to modify articles on Wikipedia. And now that I'm thinking about it, I've never seen a "report" button on any article.
You don't need to "report" it to anybody, you can do it yourself. That's why there is no report button. On the "View History" tab on the page, you can see all revisions of it. Find the offending revision, (most likely the latest one) and click undo next to the revision.