TYPO3 Core

Users might share URLs from the backend, e.g. https://example.com/typo3/module/site/configuration/edit?site=example_site
Those URLs end up in the initial start module instead of actually being opened.
This also affects custom modules by users, not only TYPO3 core modules.

The redirect only works for some routes with special hard coded handling.

The issue seems to be within TYPO3\CMS\Backend\Controller\BackendController->getStartupModule() where the name from redirect is used as a module instead of the actual module.
The redirect transports the route identifier, not the module identifier. Therefore the route identifier needs to be resolved to the module for proper check.

1. Create a site
2. Navigate to site module
3. Edit the given site
4. Copy the URL and open it within a new tab

Expected: The edit form of the site is shown
Actual: The dashboard (first module) is shown