diff --git a/CHANGELOG b/CHANGELOG
index be351680c..4004eaacf 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -72,6 +72,7 @@ CHANGELOG Roundcube Webmail
 - Fix handling of HTML entity strings in plain text messages
 - Fix focused elements aren't unfocused when clicking on the list (#1487123)
 - Fix error in MSSQL DDL scripts (#1487112)
+- Lock submit button in onsubmit event on login page (#1487036)
 
 RELEASE 0.4.2
 -------------
diff --git a/program/js/app.js b/program/js/app.js
index 7c38b142a..7ab31cb46 100644
--- a/program/js/app.js
+++ b/program/js/app.js
@@ -378,10 +378,11 @@ function rcube_webmail()
         // detect client timezone
         $('#rcmlogintz').val(new Date().getTimezoneOffset() / -60);
 
-        // display 'loading' message on form submit
+        // display 'loading' message on form submit, lock submit button
         $('form').submit(function () {
-          rcmail.display_message(rcmail.get_label('loading'), 'loading');
-        }); 
+          $('input[type=submit]', this).attr('disabled', true);
+          rcmail.display_message('', 'loading');
+        });
 
         this.enable_command('login', true);
         break;