diff --git a/app/models/metadata_template.rb b/app/models/metadata_template.rb
index 7a4fb6f..375a20f 100644
--- a/app/models/metadata_template.rb
+++ b/app/models/metadata_template.rb
@@ -85,7 +85,7 @@ MetadataTemplate = Struct.new(:site, :document, :name, :label, :type,
 
     sanitizer.sanitize(string,
                        tags: allowed_tags,
-                       attributes: allowed_attributes,
+                       attributes: allowed_attributes + %w[data-trix-attachment],
                        scrubber: scrubber).strip.html_safe
   end
 end