Kimai is an open-source time tracking application. Prior to 2.58.0, POST /api/teams/{id}/members/{userId} and POST /api/teams/{id}/activities/{activityId} verify that a teamlead may edit the Team but do not verify access_user for the referenced User or view access for the referenced Activity. A teamlead can add users or activities outside the teamlead's manageable scope to an editable team, bypassing the narrower choices enforced by TeamEditForm and UserRepository::getQueryBuilderForFormType(). The resulting relationships can be trusted by RolePermissionManager::checkTeamAccessActivity() and other team-based authorization, visibility, reporting, and workflow logic. This issue is fixed in version 2.58.0.