CVE-2026-81892: EasyAdmin custom-action dispatcher bypasses access_control on other routes

EasyAdmin serves all backend requests through a single dashboard route and, for custom actions (Action::linkToRoute() / MenuItem::linkToRoute()), swaps the executed controller based on the routeName query parameter on the kernel.controller event.

That swap happens after Symfony’s security firewall has already evaluated access_control against the original dashboard URL, and the routeName value was not validated. As a result, a path-based access_control rule protecting the target route was never evaluated, so a low-privilege backend user could reach a more restricted route by name.