This is a followup post related to this issue. I have proposed a solution to this problem in a previous post. In short the solution was to download a certificate file from Mozilla and add this information to $CURL_OPTS array in base_facebook.php file.
The second point I want to make is this. Previously I suggested appending CURLOPT_CAINFO to $CURL_OPTS array in base_facebook.php file. Now I think it will be better if I change the location information from my client code and not touch facebook.php library code. Here is how I did it:
In my client code:
$facebook = new Facebook(array( 'appId' => 'some app id', 'secret' => 'some secret', 'cookie' => true, ));
That way you can update facebook sdk library code without worrying that will have to update the certificate file path every time.