Summary The Timesheet API "PATCH /api/timesheets/{id}" and "POST /api/timesheets" endpoints accept a user-supplied "project" ID and resolve it through a Symfony "EntityType" whose "query_builder" allows the submitted ID to satisfy the access predicate via an unconditional OR branch. As a result, any authenticated user can re-assign their own timesheet to any project in the database — including projects that belong to teams or customers they have no membership in and cannot otherwise see. The user can then read serialized project/customer details via "GET /api/timesheets/{id}?full=true", leaking metadata (name, currency, customer hierarchy) that would otherwise be filtered out by the team ACL. Details Entry point — only ownership is checked in "src/API/TimesheetController.php:317-355" #[IsGranted('edit', 'timesheet')] #[Route(methods: ['PATCH'], path: '/{id}', name: 'patch_timesheet', requirements: ['id' => '\d+'])] public function patchAction(Request $request, Timesheet $timesheet): Response { ... $form = $this->createForm(TimesheetApiEditForm::class, $timesheet, [...]); $form->setData($timesheet); $form->submit($request->request->all(), false); if (false === $form->isValid()) { ... } $this->service->saveTimesheet($timesheet); ... } "src/Voter/TimesheetVoter.php:134-142": if ($subject->getUser()?->getId() === $user->getId()) { return $this->permissionManager->hasRolePermission($user, $permission . '_own_timesheet'); } if (!$this->permissionManager->checkTeamAccessTimesheet($subject, $user)) { return false; } For an own-timesheet, only "edit_own_timesheet" is required. The voter does not look at the new project being submitted; it only validates the existing record's ownership. Form replays user-controlled project ID into the access query "src/Form/TimesheetEditForm.php:60-71": $isNew = true; if (isset($options['data']) && $options['data'] instanceof Timesheet) { ... if (null !== $entry->getId()) { $isNew = false; } ... } $this->addProject($builder, $isNew, $project, $customer); "src/Form/FormTrait.php:59-100": $builder->addEventListener( FormEvents::PRE_SUBMIT, function (FormEvent $event) use ($builder, $project, $customer, $isNew, $options): void { $data = $event->getData(); $customer = \array_key_exists('customer', $data) && $data['customer'] !== '' ? $data['customer'] : null; $project = \array_key_exists('project', $data) && $data['project'] !== '' ? $data['project'] : $project; $event->getForm()->add('project', ProjectType::class, array_merge($options, [ 'group_by' => null, 'query_builder' => function (ProjectRepository $repo) use ($builder, $project, $customer, $isNew) { $project = \is_string($project) ? (int) $project : $project; ... if ($isNew && \is_int($project)) { $project = $repo->find($project); if ($project !== null) { if (!$project->getCustomer()->isVisible()) { ... $project = null; } elseif (!$project->isVisible()) { $project = null; } } } ... $query = new ProjectFormTypeQuery($project, $customer); $query->setUser($builder->getOption('user')); $query->setWithCustomer(true); return $repo->getQueryBuilderForFormType($query); }, ])); } ); Two problems compound: 1. The visibility re-check on line 73 is gated on "$isNew". For PATCH, "$isNew = false", so the closure passes the attacker-supplied ID straight through. 2. Even when "$isNew = true" (POST), the re-check only validates "isVisible()" — it does not validate team membership. The query-builder unconditionally accepts the submitted ID "src/Repository/ProjectRepository.php:150-208": public function getQueryBuilderForFormType(ProjectFormTypeQuery $query): QueryBuilder { ... $mainQuery = $qb->expr()->andX(); $mainQuery->add($qb->expr()->eq('p.visible', ':visible')); $mainQuery->add($qb->expr()->eq('c.visible', ':customer_visible')); if (!$query->isIgnoreDate()) { ... } if ($query->hasCustomers()) { ... } $permissions = $this->getPermissionCriteria($qb, $query->getUser(), $query->getTeams()); if ($permissions->count() > 0) { $mainQuery->add($permissions); } $outerQuery = $qb->expr()->orX(); if ($query->hasProjects()) { $outerQuery->add($qb->expr()->in('p.id', ':project')); // <-- unconditional $qb->setParameter('project', $query->getProjects()); } ... $outerQuery->add($mainQuery); $qb->andWhere($outerQuery); return $qb; } The final WHERE clause is roughly: WHERE (p.id IN (:project)) OR (p.visible AND c.visible AND <date> AND <team-ACL>) Because ":project" is the submitted ID itself, the first branch matches unconditionally, completely bypassing the team-ACL applied by "getPermissionCriteria". Symfony's "EntityType" happily resolves the foreign "Project" entity, the form passes validation, and the timesheet is persisted with the new "project_id". No downstream validation closes the gap - "TimesheetService::saveTimesheet" → "updateTimesheet" ("src/Timesheet/TimesheetService.php:154-177") is explicitly documented as not validating. - "TimesheetBasicValidator" only validates begin/end and project/activity coherence. - "TimesheetDeactivatedValidator::validateActivityAndProject" ("src/Validator/Constraints/TimesheetDeactivatedValidator.php:36-42") returns early for non-running existing timesheets. - No validator anywhere in the timesheet pipeline checks that the project's team membership intersects the acting user's teams. A PoC was provided, but removed for security reasons. Impact - Integrity: any authenticated user can attribute their own tracked time to any project ID in the database — including projects belonging to teams/customers they cannot see. This pollutes per-project budgets, billing exports and reports for other teams. There is no in-app warning that records belonging to outsiders have been added. - Confidentiality: by reading the timesheet back via "?full=true", the attacker obtains serialized project and customer details (name, currency, start/end dates, customer hierarchy) which would normally be filtered by the team ACL. - Privilege model: the "edit_own_timesheet" permission is part of the default ROLE_USER, so the bypass is reachable by every regular user without any administrator action. The blast radius is bounded by what an attacker can persist (their own timesheet rows) and what the "?full=true" serializer exposes — there is no direct ability to modify other teams' existing data. Solution - The FormTrait was updated to only pass the project forward for new timesheets - A new "TimesheetTeamAccessValidator"was added, which checks if "project" or "activity" were changed. If that is the case, the team access permission is checked first Find out more at "https://www.kimai.org/en/security/ghsa-vrr2-g9gh-c3jc" (https://www.kimai.org/en/security/ghsa-vrr2-g9gh-c3jc)