diff --git a/src/wp-includes/wp-db.php b/src/wp-includes/wp-db.php
index b57d572fdd..170c29565e 100644
--- a/src/wp-includes/wp-db.php
+++ b/src/wp-includes/wp-db.php
@@ -1315,7 +1315,7 @@ class wpdb {
 			$host = $this->dbhost;
 			$port_or_socket = strstr( $host, ':' );
 			if ( ! empty( $port_or_socket ) ) {
-				$host = strstr( $host, ':', true );
+				$host = substr( $host, 0, strpos( $host, ':' ) );
 				$port_or_socket = substr( $port_or_socket, 1 );
 				if ( 0 !== strpos( $port_or_socket, '/' ) ) {
 					$port = intval( $port_or_socket );