Payment services provider PayPal is vulnerable to an authentication restriction bypass vulnerability, which could allow an attacker to bypass a filter or restriction to get unauthorized access to a blocked users’ PayPal account. The vulnerability affects the iOS mobile application for both iPhone and iPad, as it fails to check for the restriction flags that would not allow access to the blocked or temporarily blocked account. A video demonstration of the vulnerability has also been published by the researcher, showing how he intentionally enters the wrong username several times in order to have his PayPal account blocked.
Source: https://thehackernews.com/2014/10/authentication-flaw-in-paypal-mobile.html