Laravel Security Release 5.6.15 and 5.5.40
Yesterday, Felix Wiedemann (https://github.com/Nilix007) alerted me to a potential exploit of the Laravel Encrypter component that may cause the Encrypter to fail on decryption and unexpectedly return
To exploit this, the attacker must be able to modify the encrypted payload before it is decrypted. Depending on the code within your application, this could lead to unexpected behavior when combined with weak type comparisons, for example:
Of course, this is likely an uncommon scenario; however, we have released a security update today to address this situation and force the Encrypter to throw an exception when it occurs.