diff --git a/addons/sale/controllers/portal.py b/addons/sale/controllers/portal.py
index 716ef4006e3..6b2639e38a2 100644
--- a/addons/sale/controllers/portal.py
+++ b/addons/sale/controllers/portal.py
@@ -3,7 +3,7 @@
 
 import binascii
 
-from odoo import fields, http, _
+from odoo import fields, http, SUPERUSER_ID, _
 from odoo.exceptions import AccessError, MissingError, ValidationError
 from odoo.fields import Command
 from odoo.http import request
@@ -256,7 +256,7 @@ class CustomerPortal(portal.CustomerPortal):
             order_sudo.action_confirm()
             order_sudo._send_order_confirmation_mail()
 
-        pdf = request.env.ref('sale.action_report_saleorder').sudo()._render_qweb_pdf([order_sudo.id])[0]
+        pdf = request.env.ref('sale.action_report_saleorder').with_user(SUPERUSER_ID)._render_qweb_pdf([order_sudo.id])[0]
 
         _message_post_helper(
             'sale.order', order_sudo.id, _('Order signed by %s') % (name,),