    protected function getFooService()
    {
        $a = new \App\Bar();

        $b = new \App\Baz($a);
        $b->bar = $a;

        $this->services['App\\Foo'] = $instance = new \App\Foo($b);

        $a->foo = $instance;

        return $instance;
    }
The software constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component.