Looks like on Samsung devices, every app has full r/w memory acess via /dev/exynos-mem I wonder two things: 1) if this is Samsung only or if its an Android is

Looks like on Samsung devices, every app has full r/w memory acess via /dev/exynos-mem I wonder two things: 1) if this is Samsung only or if its an Android issue. 2) If and how this can bee used to become root. TFA says "The good news is we can easily obtain root on these devices" but doesnt say how.