This affects the package passport before 0.6.0. When a user logs in or logs out, the session is regenerated instead of being closed.
Shopware is an open commerce platform based on the Symfony php Framework and the Vue javascript framework. In affected versions guest sessions are shared between customers when HTTP cache is enabled. This can lead to inconsistent experiences for guest users. Setups with Varnish are not affected by this issue. This issue has been resolved in version 6.4.8.2. Users unable to upgrade should disable the HTTP Cache.