I think Hanlon's razor applies. This sort of shoddy work was pretty common in early Android phones, as companies with little software experience adapted to being OS vendors.
> The kernel in Samsung Galaxy S2, Galaxy Note 2, MEIZU MX, and possibly other Android devices, when running an Exynos 4210 or 4412 processor, uses weak permissions (0666) for /dev/exynos-mem, which allows attackers to read or write arbitrary physical memory and gain privileges via a crafted application, as demonstrated by ExynosAbuse.
Here's another similar in concept (though much worse) one from Samsung: https://nvd.nist.gov/vuln/detail/CVE-2012-6422