Earlier quoted context omitted.
Grsecurity generally focuses on the kernel side of things, although it does include a number of userspace mitigations as well. Still, when you have such ripe primitives not even Grsecurity can protect you. What we really need is to just have radically lower bug density. Buffer overflows need to die. UAFs need to be made far less common. The "distance" between vulns needs to be greatly increased. Having design and val…
Grsec would make achieving code exec much harder or impossible.
Maybe if it's a stack based overflow something like PAX_RANDUSTACK would have had some impact but it depends.
And in case this at all comes off as me thinking anything negative about Grsecurity, I assure you that's not the case. I proudly wear the "Grsecurity Cheerleader" badge that Spender threw my way over a decade ago.