Ticket #39223: 39223.3.patch

wp-includes/ms-functions.php

@@ -720 +720 @@
         $user_email = sanitize_email( $user_email );
         $key = substr( md5( time() . wp_rand() . $user_email ), 0, 16 );
 
+        /**
+         * Filters the metadata for a user signup
+         *
+         * The metadata will be serialized prior to storing it in the database
+         *
+         * @since 4.8.0
+         *
+         * @param array  $meta       Signup meta data. Default empty array.
+         * @param string $user       The user's requested login name.
+         * @param string $user_email The user's email address.
+         * @param string $key        The user's activation key.
+         */
+        $meta = apply_filters( 'user_signup_meta', $meta, $user, $user_email, $key );
+
         $wpdb->insert( $wpdb->signups, array(
                 'domain' => '',
                 'path' => '',