Use of Cache Containing Sensitive Information

Summary

Shopware is an open commerce platform based on Symfony Framework and Vue. The Symfony Session Handler pops the Session Cookie and assigns it to the Response. Shopware versions 6.5.8.0 through 6.5.8.6 and 6.6.0.0-rc1 through 6.6.0.0-rc4, the 404 pages are cached to improve the performance of 404 pages. So the cached Response which contains a Session Cookie when the Browser accessing the 404 page, has no cookies yet. The Symfony Session Handler is in use, when no explicit Session configuration has been done. When Redis is in use for Sessions using the PHP Redis extension, this exploiting code is not used. As a workaround, use Redis for Sessions, as this does not trigger the exploit code.