diff --git a/lib/telnet.c b/lib/telnet.c
index 6e1f52b7f70ceca9b39c856e2e944f4b0d8c84dc..aea7749751b6b93b6945b5c8b26cd70113c10881 100644
--- a/lib/telnet.c
+++ b/lib/telnet.c
@@ -856,8 +856,8 @@ static void suboption(struct connectdata *conn)
 {
   struct curl_slist *v;
   unsigned char temp[2048];
-  int len;
-  int tmplen;
+  size_t len;
+  size_t tmplen;
   char varname[128];
   char varval[128];
   struct SessionHandle *data = conn->data;