diff --git a/wp-includes/class-wp-customize-manager.php b/wp-includes/class-wp-customize-manager.php
index 9ba93c575c..3c9de49f9e 100644
--- a/wp-includes/class-wp-customize-manager.php
+++ b/wp-includes/class-wp-customize-manager.php
@@ -2278,7 +2278,7 @@ final class WP_Customize_Manager {
 
 		// Amend post values with any supplied data.
 		foreach ( $args['data'] as $setting_id => $setting_params ) {
-			if ( array_key_exists( 'value', $setting_params ) ) {
+			if ( is_array( $setting_params ) && array_key_exists( 'value', $setting_params ) ) {
 				$this->set_post_value( $setting_id, $setting_params['value'] ); // Add to post values so that they can be validated and sanitized.
 			}
 		}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 730504ff12..551d14e55a 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-alpha-41242';
+$wp_version = '4.9-alpha-41243';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.