Problem with OAuth

How it was found

There are many website that tracks the unfollowers and all like: http://unfollowerstats.com [Steps]:

1. Login with ur twitter account, i.e. [email protected]

2. Open http://unfollowerstats.com, This will ask you to login with twitter:

3. you will get a link like this: https://api.twitter.com/oauth/authenticate?oauth_token=xpXP21WOzwvsocu7yjQBafl8BKRtKdeH

Open Another browser and login with some other user i.e. : [email protected] 5. Open this oAuth link(https://api.twitter.com/oauth/authenticate?oauth_token=xpXP21WOzwvsocu7yjQBafl8BKRtKdeH) on the other browser 6. Authorize this OAuth with user [email protected]

7. Go to the first browser, and refresh the page and continue to authorize. You will be logged into http://unfollowerstats.com with [email protected] user

-- Tested with 2 such websites