SA-CONTRIB-2026-257: Critical severity composer/drupal/commerce vulnerability

This module enables you to sell goods and services to customers through a shopping cart and checkout form. Sites can also create multiple online stores that are managed by different users. The module doesn't check access properly when a store is saved. A user who can either create stores or edit their own store is able to mark their store as the site's default store. This causes their store to get some orders they normally shouldn't. Only sites that give those permissions to untrusted users are affected (for example, marketplace sites where vendors manage their own stores).