In this challenge, we need to exploit V8 JavaScript engine with heap sandbox enabled. The bug is very simple: an array OOB. We bypass the sandbox by rewriting code field of function object, so that we can control the low 32 bits of rip register. We write the shellcode as double floating point immediate numbers in function and compile this function using JIT, and and set rip to address of the shellcode to execute execve.

Original writeup (https://mem2019.github.io/jekyll/update/2022/02/06/DiceCTF-Memory-Hole.html).