Any device that uses the Internet is only as secure as the Internet allows it. This means that there is only a limited amount of security for any application that can be found on the Internet. Hackers are always hacking into devices and apps through the Internet in order to extract information or change it without the user knowing or allowing it.
Even those apps that say they are completely secure, they can’t make that statement and be honest about it because they can only be secure enough that is able from the Internet. Most apps have enlisted in security measures prior to releasing it to the public and allow public access. This is done because the company may have issues later if they did not provide security to their users.