diff --git a/src/wp-includes/kses.php b/src/wp-includes/kses.php
index 0b552955e2..7399e9cf87 100644
--- a/src/wp-includes/kses.php
+++ b/src/wp-includes/kses.php
@@ -119,6 +119,14 @@ if ( ! CUSTOM_TAGS ) {
 			'valign' => true,
 			'width' => true,
 		),
+                'colgroup' => array(
+			'align' => true,
+			'char' => true,
+			'charoff' => true,
+			'span' => true,
+			'valign' => true,
+			'width' => true,
+		),
 		'del' => array(
 			'datetime' => true,
 		),