diff --git a/components/script/dom/servoparser/html.rs b/components/script/dom/servoparser/html.rs
index 07848c87678..7fd0429612a 100644
--- a/components/script/dom/servoparser/html.rs
+++ b/components/script/dom/servoparser/html.rs
@@ -302,11 +302,10 @@ pub(crate) fn serialize_html_fragment<S: Serializer>(
                     serializer.write_processing_instruction(pi.target(), &data)?;
                 },
 
-                NodeTypeId::DocumentFragment(_) => {},
+                NodeTypeId::DocumentFragment(_) | NodeTypeId::Attr => {},
 
                 NodeTypeId::Document(_) => panic!("Can't serialize Document node itself"),
                 NodeTypeId::Element(_) => panic!("Element shouldn't appear here"),
-                NodeTypeId::Attr => panic!("Attr shouldn't appear here"),
             },
             SerializationCommand::SerializeShadowRoot(shadow_root) => {
                 // Shadow roots are serialized as template elements with a fixed set of
diff --git a/tests/wpt/meta/MANIFEST.json b/tests/wpt/meta/MANIFEST.json
index 1469a123dd5..df2beac06bd 100644
--- a/tests/wpt/meta/MANIFEST.json
+++ b/tests/wpt/meta/MANIFEST.json
@@ -627813,7 +627813,7 @@
      ]
     ],
     "XMLSerializer-serializeToString.html": [
-     "6c294e464a5dc787abd4d10281ab2fe0555a0a3c",
+     "352a62c7d5db0710da6819bbc094ebfae46f4099",
      [
       null,
       {}
diff --git a/tests/wpt/tests/domparsing/XMLSerializer-serializeToString.html b/tests/wpt/tests/domparsing/XMLSerializer-serializeToString.html
index 6c294e464a5..352a62c7d5d 100644
--- a/tests/wpt/tests/domparsing/XMLSerializer-serializeToString.html
+++ b/tests/wpt/tests/domparsing/XMLSerializer-serializeToString.html
@@ -256,6 +256,10 @@ test(function () {
   root.setAttributeNS(XMLNS_URI, 'xmlns:foo', '');
   assert_equals(serialize(root), '<root xmlns="" xmlns:foo=""/>');
 }, 'Check if a prefix bound to an empty namespace URI ("no namespace") serialize');
+
+test(function() {
+  assert_equals(serialize(document.createAttribute("foobar")), "")
+}, 'Attribute nodes are serialized as the empty string')
 </script>
  </body>
 </html>