Find vulnerabilities before anyone else does. Zero days aren’t magic—they’re missed opportunities. From Day Zero to Zero Day teaches you how to find them before anyone else does. In this hands-on guide, award-winning white-hat hacker Eugene “Spaceraccoon” Lim breaks down the real-world process of vulnerability discovery. You’ll retrace the steps behind past CVEs, analyze open source and embedded targets, and build a repeatable workflow for uncovering critical flaws in code. Whether you’re new to vulnerability research or sharpening an existing skill set, this book will show you how to think—and work—like a bug hunter. You’ll learn how to: Identify promising targets across codebases, protocols, and file formats. Trace code paths with taint analysis and map attack surfaces with precision. Reverse engineer binaries using Ghidra, Frida, and angr. Apply coverage-guided fuzzing, symbolic execution, and variant analysis. Build and validate proof-of-concept exploits to demonstrate real-world impact. More than a toolkit, this is a window into how top vulnerability researchers approach the work. You’ll gain not just techniques but also the mindset to go deeper, ask better questions, and find what others miss. If you’re ready to stop reading write-ups and start writing them, From Day Zero to Zero Day is your guide.