Options, Meta APIs: Send a notification to the old admin email address when the site admin email or network admin email address is changed.

This reduces the chances of a site compromise going unnoticed, in the same way that the same notifications for user account email address changes reduces the chances of a user account compromise going unnoticed.

Props MatheusGimenez, johnbillion

Fixes #39117


git-svn-id: https://develop.svn.wordpress.org/trunk@41164 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/admin-filters.php

@@ -54,6 +54,7 @@ add_action( 'admin_print_scripts-post-new.php', 'wp_page_reload_on_back_button_j
 add_action( 'update_option_home',          'update_home_siteurl', 10, 2 );
 add_action( 'update_option_siteurl',       'update_home_siteurl', 10, 2 );
 add_action( 'update_option_page_on_front', 'update_home_siteurl', 10, 2 );
+add_action( 'update_option_admin_email',   'wp_site_admin_email_change_notification', 10, 3 );
 
 add_filter( 'heartbeat_received', 'wp_check_locked_posts',  10,  3 );
 add_filter( 'heartbeat_received', 'wp_refresh_post_lock',   10,  3 );

src/wp-admin/includes/ms-admin-filters.php

@@ -22,6 +22,9 @@ add_action( 'update_option_new_admin_email', 'update_option_new_admin_email', 10
 // Site Hooks.
 add_action( 'wpmueditblogaction', 'upload_space_setting' );
 
+// Network hooks
+add_action( 'update_site_option_admin_email', 'wp_network_admin_email_change_notification', 10, 4 );
+
 // Taxonomy Hooks
 add_filter( 'get_term', 'sync_category_tag_slugs', 10, 2 );