diff --git a/src/wp-includes/class-wp-user.php b/src/wp-includes/class-wp-user.php
index fb79242f5f..620aecd024 100644
--- a/src/wp-includes/class-wp-user.php
+++ b/src/wp-includes/class-wp-user.php
@@ -240,7 +240,7 @@ class WP_User {
 
 		if ( ! $user = $wpdb->get_row(
 			$wpdb->prepare(
-				"SELECT * FROM $wpdb->users WHERE $db_field = %s",
+				"SELECT * FROM $wpdb->users WHERE $db_field = %s LIMIT 1",
 				$value
 			)
 		) ) {