diff --git a/app/helpers/gitlab_markdown_helper.rb b/app/helpers/gitlab_markdown_helper.rb
index 18ce07a..9da695b 100644
--- a/app/helpers/gitlab_markdown_helper.rb
+++ b/app/helpers/gitlab_markdown_helper.rb
@@ -31,7 +31,7 @@ module GitlabMarkdownHelper
       extractions[$1]
     end
 
-    sanitize text.html_safe
+    sanitize text.html_safe, attributes:  ActionView::Base.sanitized_allowed_attributes + %w(id class )
   end
 
   # Use this in places where you would normally use link_to(gfm(...), ...).
--
libgit2 0.21.2