diff --git a/invenio.cfg b/invenio.cfg
index 77949aa5..aef0db99 100644
--- a/invenio.cfg
+++ b/invenio.cfg
@@ -108,6 +108,9 @@ APP_DEFAULT_SECURE_HEADERS = {
             "ajax.googleapis.com",
             # For CERN Matomo
             "webanalytics.web.cern.ch",
+            # For MathType - (TinyMCE Plugin)
+            "https://www.wiris.net",
+            "https://data.wiris.cloud",
         ],
     },
     'content_security_policy_report_only': False,