diff --git a/src/packet_cb.c b/src/packet_cb.c
index 0fee5d48..6228b44a 100644
--- a/src/packet_cb.c
+++ b/src/packet_cb.c
@@ -178,7 +178,7 @@ SSH_PACKET_CALLBACK(ssh_packet_newkeys)
         session->dh_handshake_state=DH_STATE_FINISHED;
     } else {
 #ifdef WITH_GSSAPI
-        if (session->opts.gssapi_key_exchange) {
+        if (ssh_kex_is_gss(session->next_crypto)) {
             OM_uint32 maj_stat, min_stat;
             gss_buffer_desc mic = GSS_C_EMPTY_BUFFER, msg = GSS_C_EMPTY_BUFFER;
 
@@ -187,6 +187,13 @@ SSH_PACKET_CALLBACK(ssh_packet_newkeys)
                 goto error;
             }
 
+            if (session->gssapi_key_exchange_mic == NULL) {
+                ssh_set_error(session,
+                              SSH_FATAL,
+                              "GSSAPI mic not set");
+                goto error;
+            }
+
             mic.length = ssh_string_len(session->gssapi_key_exchange_mic);
             mic.value = ssh_string_data(session->gssapi_key_exchange_mic);
 
@@ -271,6 +278,9 @@ SSH_PACKET_CALLBACK(ssh_packet_newkeys)
     return SSH_PACKET_USED;
 
 error:
+#ifdef WITH_GSSAPI
+    SSH_STRING_FREE(session->gssapi_key_exchange_mic);
+#endif
     SSH_SIGNATURE_FREE(sig);
     ssh_string_burn(sig_blob);
     SSH_STRING_FREE(sig_blob);