cakephp 2.0 how to update auth data?

evert0ns answer is right. But you should use AuthComponent::login(), because the data is saved within the AuthComponent as well and is not fetched from the session every time.

I had the problem just a couple of days ago.

// AppController.php
/**
 * Renews current user data, e.g. in case of an email address change while being logged in.
 *
 * @param array $newUserData
 * @return void
 */
    protected function renewUserSession($newUserData){
            if(!isset($newUserData) || empty($newUserData)){
                    return;
            }

            // We need to fetch the current user data so custom indexes are copied
            $currentUserData = $this->Auth->user();
            if(!isset($currentUserData) || empty($currentUserData)){
                    return;
            }

            // Merge old with new data
            $newUserData = array_merge($currentUserData, $newUserData);

            // Login with new data
            $this->Auth->login($newUserData);
    }

Source: my paste

Put this in your AppController. The method is specialized to merge the current and the new user data to keep existing custom indexes that you may have provided. I needed this, but you can leave it out though. Give the updated user data as a parameter to the method. Not in model find form. E.g.:

$data = array(
    'User' => array(
        'username' => 'bla',
        'passwort' => 'fu',
        'email' => 'hu@bar.com'
    )
);

// Wrong
$this->renewUserSession($data);

// Right
$this->renewUserSession($data['User']);