Recently change email but still login with old email

How it was found

Hi team, I have been found vulnerability on email verification which can be account takeover (Authentication bypass) Recently I have been change my email ████ but still login with old email ██████ --https://efss.qloud.my/index.php/settings/user

Impact

Impact If victim's email account is still logged into his/her old gmail account . Then any external attacker can use the unused same email for account takeover https://efss.qloud.my/index.php/settings/user