diff --git a/wp-includes/class-wp-customize-control.php b/wp-includes/class-wp-customize-control.php
index ca82dff71e..dc6d4758df 100644
--- a/wp-includes/class-wp-customize-control.php
+++ b/wp-includes/class-wp-customize-control.php
@@ -632,8 +632,8 @@ class WP_Customize_Control {
 						?>
 					</button>
 					<div class="new-content-item">
-						<label for="create-input-<?php echo $this->id; ?>"><span class="screen-reader-text"><?php _e( 'New page title' ); ?></span></label>
-						<input type="text" id="create-input-<?php echo $this->id; ?>" class="create-item-input" placeholder="<?php esc_attr_e( 'New page title&hellip;' ); ?>">
+						<label for="create-input-<?php echo esc_attr( $this->id ); ?>"><span class="screen-reader-text"><?php _e( 'New page title' ); ?></span></label>
+						<input type="text" id="create-input-<?php echo esc_attr( $this->id ); ?>" class="create-item-input" placeholder="<?php esc_attr_e( 'New page title&hellip;' ); ?>">
 						<button type="button" class="button add-content"><?php _e( 'Add' ); ?></button>
 					</div>
 				<?php endif; ?>
@@ -675,7 +675,7 @@ class WP_Customize_Control {
 	 */
 	final public function print_template() {
 		?>
-		<script type="text/html" id="tmpl-customize-control-<?php echo $this->type; ?>-content">
+		<script type="text/html" id="tmpl-customize-control-<?php echo esc_attr( $this->type ); ?>-content">
 			<?php $this->content_template(); ?>
 		</script>
 		<?php
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 8efd94cd6d..960110cf36 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51926';
+$wp_version = '5.9-alpha-51927';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.