diff --git a/app/views/shared/_mailer_round_button.html.haml b/app/views/shared/_mailer_round_button.html.haml
index 18031f176..c983e0bdc 100644
--- a/app/views/shared/_mailer_round_button.html.haml
+++ b/app/views/shared/_mailer_round_button.html.haml
@@ -5,5 +5,5 @@
       %table{ border:"0", cellspacing:"0", cellpadding:"0", style:"margin: auto" }
         %tr
           %td{ align:"center", style:"border-radius: 5px;", bgcolor:"#0069cc" }
-            %a{ href: url, target:"_blank", style:"font-size: 16px; font-family: Helvetica, Arial, sans-serif; color: #ffffff; text-decoration: none; text-decoration: none; border-radius: 5px; padding: 12px 25px; border: 1px solid #0069cc; display: inline-block;" }
+            %a{ href: url, target:"_blank", rel: "noopener", style:"font-size: 16px; font-family: Helvetica, Arial, sans-serif; color: #ffffff; text-decoration: none; text-decoration: none; border-radius: 5px; padding: 12px 25px; border: 1px solid #0069cc; display: inline-block;" }
               = text