Copy HtmlHelper in your app directory(/app/views/helpers/html.php).
Use $options['extern'] = true to skip right check.
Find link method and just before the return statement add this code


function link($title, $url = null, $options = array(), $confirmMessage = false) {

        /**
         * ..
         * ...Original code here
         * ....
         */

        /**
         * Override link method for Acl rights checking
         */
        $extern = false;
        if (isset($options['extern'])) {
            $extern = (boolean) $options['extern'];
            unset($options['extern']);
        }
        $parsedUrl = Router::parse($url);
        if (!$extern &&
                isset($parsedUrl['controller']) &&
                isset($parsedUrl['action']) &&
                strpos($parsedUrl['controller'], 'mailto:') !== 0 &&
                !$this->Session->check('Auth.User.Permissions.controllers/' . Inflector::camelize($parsedUrl['controller']) . '/' . $parsedUrl['action']))
            return false;
        elseif ($extern)
            return $title;
        /**
         * End override
         */

        // don't touch this >>>
        return sprintf($this->tags['link'], $url, $this->_parseAttributes($options), $title);
    }

Also add at the begining:

       var $helpers = array("Session");

To store user rights you need to add this in login() or somewhere where is being executed when user logs in.


    function login() {
        if ($userId = $this->Session->read('Auth.User.id')) {
            $acos = $this->Acl->Aco->children();
            foreach ($acos as $aco) {
                $tmpacos = $this->Acl->Aco->getPath($aco['Aco']['id']);
                $path = array();
                foreach ($tmpacos as $tmpaco) {
                    $path[] = $tmpaco['Aco']['alias'];
                }
                $stringPath = implode('/', $path);
                if ($this->Acl->check(array('model' => 'User', 'foreign_key' => $userId), $stringPath))
                    $permissions[$stringPath] = true;
            }
            $this->Session->write('Auth.User.Permissions', $permissions);
        }
        if (is_array($this->Session->read('Auth.User'))) {
            $this->redirect('/');
        }
    }
Login code can be improved for faster performance.