rss feed widget not working

We have a lot of wordpress site on our server.

In november we updated all at version 3.7.1. We noticed an issue with the rss feed widget. Before updating we was in 3.4.1

After a lot of troubleshooting we have found the issue but we don’t know how to fix it.

The issue is in the function wp_http_validate_url at line 483 in the file http.php.

There’s the code
if ( ‘127.0.0.1’ === $ip || ( 10 === $parts[0] )
|| ( 172 === $parts[0] && 16 <= $parts[1] && 31 >= $parts[1] )
|| ( 192 === $parts[0] && 168 === $parts[1] )

I understand with this code is wordpress doesn’t allow feeding rss on other site hosted on server with ip 192.168 or 10. These ip are always use as internal adress. Our server have a 192.168 so we have the issue

We tried to bypass this validation and rss came back to life. We dont want to modify wordpress file it’s not the solution.

For us it’s a problem because we have roughly 100 wp site on the same server and a lot of them are linked each other by rss feed widget.

How can we cleanly fix it?