diff --git a/cmd-run-shell.c b/cmd-run-shell.c
index 5f207bbb..bc21cc9c 100644
--- a/cmd-run-shell.c
+++ b/cmd-run-shell.c
@@ -114,7 +114,8 @@ cmd_run_shell_exec(struct cmd *self, struct cmdq_item *item)
 
 	cdata->cwd = xstrdup(server_client_get_cwd(item->client, s));
 	cdata->s = s;
-	session_add_ref(s, __func__);
+	if (s != NULL)
+		session_add_ref(s, __func__);
 
 	evtimer_set(&cdata->timer, cmd_run_shell_timer, cdata);
 
@@ -203,7 +204,8 @@ cmd_run_shell_free(void *data)
 	struct cmd_run_shell_data	*cdata = data;
 
 	evtimer_del(&cdata->timer);
-	session_remove_ref(cdata->s, __func__);
+	if (cdata->s != NULL)
+		session_remove_ref(cdata->s, __func__);
 	free(cdata->cwd);
 	free(cdata->cmd);
 	free(cdata);