diff --git a/firebase.json b/firebase.json
index d9ab92c..7579574 100644
--- a/firebase.json
+++ b/firebase.json
@@ -7,7 +7,7 @@
         "headers": [
           {
             "key": "Content-Security-Policy",
-            "value": "block-all-mixed-content; default-src: 'none'; frame-ancestors 'none'; form-action 'none';"
+            "value": "block-all-mixed-content; default-src: 'none'; frame-src: 'none'; frame-ancestors 'none'; form-action 'none';"
           },
           {
             "key": "X-Content-Type-Options",