Ticket #11620: file.diff

file.php

@@ -239 +239 @@
         $upload_error_handler = 'wp_handle_upload_error';
 
         // You may have had one or more 'wp_handle_upload_prefilter' functions error out the file.  Handle that gracefully.
-        if ( isset( $file['error'] ) && !ctype_digit( $file['error'] ) && $file['error'] )
+        if ( isset( $file['error'] ) && !is_numeric( $file['error'] ) && $file['error'] )
                 return $upload_error_handler( $file, $file['error'] );
 
         // You may define your own function and pass the name in $overrides['unique_filename_callback']