diff --git a/lib/nghttp2_submit.c b/lib/nghttp2_submit.c
index 828d8f27..cc543b54 100644
--- a/lib/nghttp2_submit.c
+++ b/lib/nghttp2_submit.c
@@ -129,12 +129,15 @@ static int nghttp2_submit_headers_shared_nva
     NGHTTP2_PRIORITY_TYPE_NONE
   };
 
-  rv = nghttp2_nv_array_copy(&nva_copy, nva, nvlen);
-  if(rv < 0) {
-    return rv;
-  }
-
   if(pri_spec) {
+    switch(pri_spec->pri_type) {
+    case NGHTTP2_PRIORITY_TYPE_GROUP:
+    case NGHTTP2_PRIORITY_TYPE_DEP:
+      break;
+    default:
+      return NGHTTP2_ERR_INVALID_ARGUMENT;
+    }
+
     copy_pri_spec = *pri_spec;
 
     if(copy_pri_spec.pri_type == NGHTTP2_PRIORITY_TYPE_GROUP) {
@@ -142,6 +145,11 @@ static int nghttp2_submit_headers_shared_nva
     }
   }
 
+  rv = nghttp2_nv_array_copy(&nva_copy, nva, nvlen);
+  if(rv < 0) {
+    return rv;
+  }
+
   return nghttp2_submit_headers_shared(session, flags, stream_id,
                                        &copy_pri_spec, nva_copy, rv, data_prd,
                                        stream_user_data);
@@ -263,6 +271,10 @@ int nghttp2_submit_push_promise(nghttp2_session *session, uint8_t flags,
   nghttp2_headers_aux_data *aux_data = NULL;
   int rv;
 
+  if(!session->server) {
+    return NGHTTP2_ERR_PROTO;
+  }
+
   frame = malloc(sizeof(nghttp2_frame));
   if(frame == NULL) {
     return NGHTTP2_ERR_NOMEM;
@@ -347,7 +359,7 @@ int nghttp2_submit_altsvc(nghttp2_session *session, uint8_t flags,
   uint8_t *copy_protocol_id, *copy_host, *copy_origin;
 
   if(!session->server) {
-    return NGHTTP2_ERR_INVALID_STATE;
+    return NGHTTP2_ERR_PROTO;
   }
 
   varlen = protocol_id_len + host_len + origin_len;
diff --git a/tests/nghttp2_session_test.c b/tests/nghttp2_session_test.c
index caa068c6..5f5f451b 100644
--- a/tests/nghttp2_session_test.c
+++ b/tests/nghttp2_session_test.c
@@ -3484,7 +3484,7 @@ void test_nghttp2_submit_altsvc(void)
 
   nghttp2_session_client_new(&session, &callbacks, NULL);
 
-  CU_ASSERT(NGHTTP2_ERR_INVALID_STATE ==
+  CU_ASSERT(NGHTTP2_ERR_PROTO ==
             nghttp2_submit_altsvc(session, NGHTTP2_FLAG_NONE,
                                   0, 0, 3000,
                                   (const uint8_t*)protocol_id,
@@ -3548,7 +3548,7 @@ void test_nghttp2_submit_invalid_nv(void)
 
   memset(&callbacks, 0, sizeof(nghttp2_session_callbacks));
 
-  CU_ASSERT(0 == nghttp2_session_client_new(&session, &callbacks, NULL));
+  CU_ASSERT(0 == nghttp2_session_server_new(&session, &callbacks, NULL));
 
   /* nghttp2_submit_request */
   CU_ASSERT(0 ==