Kimai is a web-based multi-user time-tracking application. Prior to version 2.51.0, "GET /api/invoices/{id}" only checks the role-based view_invoice permission but does not verify the requesting user has access to the invoice's customer. Any user with ROLE_TEAMLEAD (which grants view_invoice) can read all invoices in the system, including those belonging to customers assigned to other teams. This issue has been patched in version 2.51.0.

Affected: Packagist: kimai/kimai

## Summary

`GET /api/invoices/{id}` only checks the role-based `view_invoice` permission but does not verify the requesting user has `access` to the invoice's customer. Any user with `ROLE_TEAMLEAD` (which grants `view_invoice`) can read all invoices in the system, including those belonging to customers assigned to other teams.

## Affected Code

`src/API/InvoiceController.php` line 92-101:

```php #[IsGranted('view_invoice')] // Role check only, no customer access check #[Route(methods: ['GET'], path: '/{id}', name: 'get_invoice', requirements: ['id' => '\d+'])] public function getAction(Invoice $invoice): Response { $view = new View($invoice, 200); $view->getContext()->setGroups(self::GROUPS_ENTITY); return $this->viewHandler->handle($view); // Returns ANY invoice by ID } ```

The web controller (`src/Controller/InvoiceController.php` line 304-307) correctly checks customer access:

```php #[IsGranted('view_invoice')] #[IsGranted(new Expression("is_granted('access', subject.getCustomer())"), 'invoice')] public function downloadAction(Invoice $invoice, ...): Response { ... } ```

The `access` attribute in `CustomerVoter` (line 71-87) verifies team membership, but this check is entirely missing from the API endpoint.

## PoC

Tested against Kimai v2.50.0 (Docker: `kimai/kimai2:apache`).

Setup: - TeamA with CustomerA ("SecretCorp"), TeamB with CustomerB ("BobCorp") - Bob is a teamlead in TeamB only - An invoice exists for SecretCorp (TeamA)

```bash #…