JavaScript Engines Under Siege: Building Defenses Against JIT Exploits

JavaScript JIT compilers are critical but dangerous: they compile untrusted code directly into optimized native machine code, creating powerful leverage points for attackers. The article explores how type confusion, use-after-free, and other JIT vulnerabilities escalate to full sandbox escapes, and demonstrates practical hardening techniques—CFI, pointer authentication, memory tagging—that maintain performance while significantly raising exploitation costs.