    public function gc($force = false)
    {
        if ($force || mt_rand(0, 1000000) < $this->gcProbability) {
            $this->db->createCommand()
                ->delete($this->cacheTable, '[[expire]] > 0 AND [[expire]] < ' . time())
                ->execute();
        }
    }
The software uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.