diff --git a/lib/http_proxy.c b/lib/http_proxy.c
index 5c5f8fb2c..5a1dc0b86 100644
--- a/lib/http_proxy.c
+++ b/lib/http_proxy.c
@@ -410,7 +410,8 @@ static CURLcode CONNECT(struct connectdata *conn,
         }
 
         /* convert from the network encoding */
-        result = Curl_convert_from_network(data, line_start, perline);
+        result = Curl_convert_from_network(data, s->line_start,
+                                           (size_t)s->perline);
         /* Curl_convert_from_network calls failf if unsuccessful */
         if(result)
           return result;