Index: src/wp-includes/widgets.php
===================================================================
--- src/wp-includes/widgets.php	(revision 43272)
+++ src/wp-includes/widgets.php	(working copy)
@@ -426,7 +426,7 @@
 	global $wp_registered_sidebars;
 
 	if ( isset( $wp_registered_sidebars[ $id ]['description'] ) ) {
-		return esc_html( $wp_registered_sidebars[ $id ]['description'] );
+		return wp_kses( $wp_registered_sidebars[ $id ]['description'], 'sidebar_description' );
 	}
 }