diff --git a/superset/config.py b/superset/config.py
index c5fc120f10ff1..20735a77ec58d 100644
--- a/superset/config.py
+++ b/superset/config.py
@@ -1426,7 +1426,11 @@ def EMAIL_HEADER_MUTATOR(  # pylint: disable=invalid-name,unused-argument
             "https://events.mapbox.com",
         ],
         "object-src": "'none'",
-        "style-src": ["'self'", "'unsafe-inline'"],
+        "style-src": [
+            "'self'",
+            "'unsafe-inline'",
+            "https://cdn.jsdelivr.net/npm/swagger-ui-dist@5/swagger-ui.css",
+        ],
         "script-src": ["'self'", "'strict-dynamic'"],
     },
     "content_security_policy_nonce_in": ["script-src"],