diff --git a/themes/snow.js b/themes/snow.js
index 85069cec3e..4b3dba7c9f 100644
--- a/themes/snow.js
+++ b/themes/snow.js
@@ -110,7 +110,7 @@ class SnowTooltip extends BaseTooltip {
   }
 }
 SnowTooltip.TEMPLATE = [
-  '<a class="ql-preview" target="_blank" href="about:blank"></a>',
+  '<a class="ql-preview" rel="noopener noreferrer" target="_blank" href="about:blank"></a>',
   '<input type="text" data-formula="e=mc^2" data-link="https://quilljs.com" data-video="Embed URL">',
   '<a class="ql-action"></a>',
   '<a class="ql-remove"></a>'