Custom web fonts via CDN (or any cross-domain font request) doesn’t work in Firefox or Internet Explorer (correctly so, by spec) though they do work (incorrectly so) in Webkit-based browsers.
You can fix this by adding headers to your page.
Apache
<FilesMatch ".(eot|ttf|otf|woff)">
Header set Access-Control-Allow-Origin "*"
</FilesMatch>
Nginx
if ($filename ~* ^.*?\.(eot)|(ttf)|(woff)$){
add_header Access-Control-Allow-Origin *;
}
Credit: http://davidwalsh.name/cdn-fonts