diff --git a/libsofia-sip-ua/sip/sip_refer.c b/libsofia-sip-ua/sip/sip_refer.c
index 83510cdcc79c72d16c3b4094b98339736010f6e2..2cf3ac4dcae0a775b21a3a43765d3ebcb5714192 100644
--- a/libsofia-sip-ua/sip/sip_refer.c
+++ b/libsofia-sip-ua/sip/sip_refer.c
@@ -226,7 +226,7 @@ issize_t sip_referred_by_d(su_home_t *home, sip_header_t *h, char *s, isize_t sl
 		      &b->b_display,
 		      b->b_url,
 		      &b->b_params,
-		      NULL) < 0)
+		      NULL) < 0 || *s /* Extra stuff? */)
     return -1;
 
   if (b->b_params)