Bad Validation Is Breeding Security Nightmares in NestJS

Basic type validation (@IsString()) isn't enough to secure your NestJS app. Without proper content validation (length limits, regex patterns, sanitization), you're vulnerable to SQL injection, XSS, and DoS attacks. Modern AI tools can help automate validation improvements across legacy codebases, but you need to implement validation systematically—every unvalidated field is a potential security breach.