patch CVE-2020-13619 (#426)
patch CVE-2020-13619 (#426)

* patch CVE-2020-13619

fixes #420

* formatting

missing a space if nothing else

* add bufix sample & credits

* update example 2

* forgot escapeshellarg() in example2
kvz/phpjs,kvz/phpjs,kvz/phpjs,kvz/phpjs