[SECURITY] Hardening: Don't use |safe on confirm_messages

src/pretix/presale/checkoutflow.py

@@ -51,6 +51,7 @@ from django.http import HttpResponseNotAllowed, JsonResponse
 from django.shortcuts import redirect
 from django.utils import translation
 from django.utils.functional import cached_property
+from django.utils.html import conditional_escape
 from django.utils.translation import (
     get_language, gettext_lazy as _, pgettext_lazy,
 )
@@ -1634,7 +1635,7 @@ class ConfirmStep(CartMixin, AsyncAction, TemplateFlowStep):
         meta_info = {
             'contact_form_data': self.cart_session.get('contact_form_data', {}),
             'confirm_messages': [
-                str(m) for m in self.confirm_messages.values()
+                conditional_escape(str(m)) for m in self.confirm_messages.values()
             ]
         }
         api_meta = {}

src/pretix/presale/signals.py

@@ -144,7 +144,7 @@ checkout_confirm_messages = EventPluginSignal()
 This signal is sent out to retrieve short messages that need to be acknowledged by the user before the
 order can be completed. This is typically used for something like "accept the terms and conditions".
 Receivers are expected to return a dictionary where the keys are globally unique identifiers for the
-message and the values can be arbitrary HTML.
+message and the values can be a SafeString containing arbitrary HTML, or a string that will be HTML-escaped.
 
 As with all event plugin signals, the ``sender`` keyword argument will contain the event.
 """

src/pretix/presale/templates/pretixpresale/event/checkout_confirm.html

@@ -176,7 +176,7 @@
                         <div class="checkbox">
                             <label for="input_confirm_{{ key }}">
                                 <input type="checkbox" class="checkbox" value="yes" name="confirm_{{ key }}" id="input_confirm_{{ key }}" required>
-                                {{ desc|safe }}
+                                {{ desc }}
                             </label>
                         </div>
                     {% endfor %}