Blog Security issue with blog
 

Yesterday a user on my forum created a blog post.

Title was


and body was



If one opened this post, he was actually redirected to google. Also, I have an external page where recent blog titles are listed. When this blog post was active, when I opened this page I got a pop-up window reading "xss".

I think this is a bad thing and would like to ask if there is a way to eliminate the possibility for my users to do such things?

I guess this is kind of urgent...

Thank you in advance!