diff --git a/web/src/components/MemoContent/CodeBlock.tsx b/web/src/components/MemoContent/CodeBlock.tsx
index 4b733015f57db..25d056cc03b3b 100644
--- a/web/src/components/MemoContent/CodeBlock.tsx
+++ b/web/src/components/MemoContent/CodeBlock.tsx
@@ -25,7 +25,17 @@ const CodeBlock: React.FC<Props> = ({ language, content }: Props) => {
   // Users can set Markdown code blocks as `__html` to render HTML directly.
   if (formatedLanguage === SpecialLanguage.HTML) {
     const purify = DOMPurify(window);
-    return <div className="w-full overflow-auto !my-2" dangerouslySetInnerHTML={{ __html: purify.sanitize(content) }} />;
+    return (
+      <div
+        className="w-full overflow-auto !my-2"
+        dangerouslySetInnerHTML={{
+          __html: purify.sanitize(content, {
+            ALLOWED_TAGS: ["iframe"],
+            ADD_ATTR: ["allow", "allowfullscreen", "frameborder", "scrolling"],
+          }),
+        }}
+      />
+    );
   } else if (formatedLanguage === SpecialLanguage.MERMAID) {
     return <MermaidBlock content={content} />;
   }