diff --git a/wp-admin/custom-header.php b/wp-admin/custom-header.php
index 14f01dfb58..7629af3d3a 100644
--- a/wp-admin/custom-header.php
+++ b/wp-admin/custom-header.php
@@ -1001,6 +1001,7 @@ wp_nonce_field( 'custom-header-options', '_wpnonce-custom-header-options' ); ?>
 
 		$default = sprintf( $default, get_template_directory_uri(), get_stylesheet_directory_uri() );
 
+		$default_data = array();
 		foreach ( $this->default_headers as $header => $details ) {
 			if ( $details['url'] == $default ) {
 				$default_data = $details;