[SECURITY] Disable outbound and file access for reportlab (CVE-2026-57535)

src/pretix/helpers/apps.py

@@ -29,3 +29,8 @@ class PretixHelpersConfig(AppConfig):
     def ready(self):
         from .monkeypatching import monkeypatch_all_at_ready
         monkeypatch_all_at_ready()
+
+        # Ensure reportlab does not make any calls to the internet
+        from reportlab import rl_config
+        rl_config.trustedHosts = []
+        rl_config.trustedSchemes = ['data']