Security Mitigations

ASLR (Address Space Layout Randomization)

ASLR for userspace is supported.

KASLR (kernel) was added with 5.0.0. PASLR (physical) was added with 10.0.0.

RelRo

Support for RelRo (read-only-relocations) was added with 17.0.0, binaries built for [17.0.0+] use this.

PAC

[S2] PAC is used for retaddrs on stack.

XOM (eXecute-Only-Memory)

Support for --X was initially added with [19.0.0+], however it's only used on S2. It's unknown when S2 enabled using this.

Sysmodules have --X .text, at least as of system-version 20.x.

CFI (Control-Flow-Integrity)

Besides the CFI used by web-applets, S2 sysmodules seem to use a version of CFI which validate vtable-ptrs (the value of the ptr, without accessing the data located there).