[BUGFIX] Do not fall back to routes on invalid “id”

Prevents a logic issue where any failure to load
a record from “pages” based on $_GET[‘id’]
would cause incorrect behavior of falling back
to the site’s configured root page.

Inability to load the page record requested with
“id” in URL must trigger pageNotFoundAction
instead of rendering the site’s root page.

Change-Id: I731f7d078a654e44b8a197b5bf5cb41a4727bbe9
Resolves: #89126
Releases: 9.5
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/61657
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Henning Liebe <h.liebe@neusta.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Henning Liebe <h.liebe@neusta.de>
Reviewed-by: Benni Mack <benni@typo3.org>

typo3/sysext/frontend/Classes/Middleware/PageResolver.php

@@ -88,7 +88,15 @@ public function process(ServerRequestInterface $request, RequestHandlerInterface
             }
 
             $requestId = (string)($request->getQueryParams()['id'] ?? '');
-            if (!empty($requestId) && !empty($page = $this->resolvePageId($requestId))) {
+            if (!empty($requestId)) {
+                $page = $this->resolvePageId($requestId);
+                if ($page === null) {
+                    return GeneralUtility::makeInstance(ErrorController::class)->pageNotFoundAction(
+                        $request,
+                        'The requested page does not exist',
+                        ['code' => PageAccessFailureReasons::PAGE_NOT_FOUND]
+                    );
+                }
                 // Legacy URIs (?id=12345) takes precedence, not matter if a route is given
                 $pageArguments = new PageArguments(
                     (int)($page['l10n_parent'] ?: $page['uid']),