I have a site which is using web font in css. It looks good in Chrome, IE, etc., except Firefox. It just shew a square with the number, something like F052.
I did a lot of search and it took me about 4 hours, until now I got the solution.
It is only happened on cross domain resource.
It is only happened on Firefox.
It is only happened when using CDN.
When I use Firebug to look at the pipe, the woff web font file is aborted. The url is corrected.
Catalin Rosu gave the solution in this post.