GHSA-h4hf-v6w5-897x: Poweradmin: API user-update endpoint leads to a non-admin reset any user's password and take over the superuser account

Summary The REST API user-update endpoint (PUT/PATCH /api/v2/users/{id} and the V1 equivalent) does not enforce two authorization rules that the web interface enforces. A user who holds the user_edit_others permission but is not a superuser can: 1. edit user accounts that belong to a superuser, and 2. set the password of any account, even without the user_passwd_edit_others permission. Because of this, a non-admin "user manager" role can send a single API request that changes the administrator's password, then log in as the administrator. This is a full privilege escalation and account takeover. The same actions are explicitly blocked in the web UI, so the API is inconsistent with the application's own permission model. Details Poweradmin's permission model treats these as three distinct permissions: - user_edit_others (id 57): "User is allowed to edit other users." - user_passwd_edit_others (id 58): "User is allowed to edit the password of other users." - user_is_ueberuser (id 53): full admin. The existence of a separate user_passwd_edit_others permission means that "edit other users" is not supposed to include changing their passwords. The web UI enforces this, and it additionally forbids any non-superuser from editing a superuser account at all. The API skips both rules. Where the API is missing the superuser check. lib/Domain/Service/ApiPermissionService.php, canEditUser(): public function canEditUser(int $userId, int $targetUserId): bool { if ($this->userHasPermission($userId, 'user_is_ueberuser')) { return true; } if ($userId === $targetUserId && $this->userHasPermission($userId, 'user_edit_own')) { return true; } // User with user_edit_others can edit ALL users, including superusers if ($this->userHasPermission($userId, 'user_edit_others')) { return true; } return false; } There is no check on whether the target is a superuser. Compare this with the web controller lib/Application/Controller/EditUserController.php (lines 237 to 243), which explicitly