diff --git a/libraries/src/Form/Rule/EmailRule.php b/libraries/src/Form/Rule/EmailRule.php
index 1d2a85329f1c1..3187b83c376c9 100644
--- a/libraries/src/Form/Rule/EmailRule.php
+++ b/libraries/src/Form/Rule/EmailRule.php
@@ -31,9 +31,10 @@ class EmailRule extends FormRule
 	 *
 	 * @var    string
 	 * @since  1.7.0
-	 * @link   http://www.w3.org/TR/html-markup/input.email.html
+	 * @link   https://www.w3.org/TR/html/sec-forms.html#email-state-typeemail
 	 */
-	protected $regex = "^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$";
+	protected $regex = "^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])"
+			. "?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$";
 
 	/**
 	 * Method to test the email address and optionally check for uniqueness.