iframe attribute

When I use the oembed feature to include videos from YouTube in my pages and posts I get the following error in my html validator.

The frameborder attribute on the iframe element is obsolete. Use CSS instead.
…_policy=1&wmode=transparent' frameborder='0'></iframe></span></strong></p>

Attribute type not allowed on element iframe at this point.
…_policy=1&wmode=transparent' frameborder='0'></iframe></span></strong></p>

I would like to use css for the framborder as the first error suggests, but how do I do remove the frameborder attribute from the html?

Thanks in advance!

This has nothing to do with theme but WordPress oEmbed and Youtube in general.

Of course you can fix it by embedding code this way

<iframe style="border:0;" width="592" height="333" src="Life is like a box of chocolates - Forrest Gump - YouTube" allowfullscreen></iframe>

but you feel free to ignore this altogether.