Find & Fix Code Vulnerabilities with Claude Code

8/10/2025

Finding & Fixing Vulnerabilities in Your Codebase with Claude Code

Hey everyone, let's talk about something that’s on every developer's mind, or at least it SHOULD be: code security. Honestly, it's one of those things that's easy to push to the back of your mind when you're deep in the zone, trying to ship a new feature or fix a pesky bug. We've all been there. But here's the thing, ignoring security is like building a house on a shaky foundation. Sooner or later, it’s going to cause some serious problems.

For years, the process of finding & fixing security vulnerabilities has been… well, a bit of a pain. Traditional static analysis tools, or SAST tools, have been a staple, but they're notorious for being noisy, flagging a ton of false positives that you have to wade through. It can feel like a chore, & it often slows down the development process. But what if I told you there's a new way to approach this, one that feels less like a roadblock & more like having a super-smart security expert sitting right next to you?

Enter Claude Code. This isn't just another linter or a basic code scanner. It's an AI-powered coding assistant that's changing the game when it comes to writing secure code. Recently, Anthropic, the minds behind Claude, rolled out some seriously cool automated security review features that are designed to help developers like us catch vulnerabilities before they ever make it into production. And let me tell you, it's pretty impressive.

So, in this article, we're going to take a deep dive into how you can use Claude Code to find & fix vulnerabilities in your codebase. We'll cover everything from the most common types of vulnerabilities to how you can integrate Claude Code into your daily workflow. I'll even share some real-world examples & best practices to help you get the most out of this powerful tool. Ready? Let's get into it.

The Ever-Present Threat of Code Vulnerabilities

Before we jump into the "how," let's quickly touch on the "why." Code vulnerabilities are a BIG deal. A single flaw can lead to devastating consequences, from data breaches that expose sensitive customer information to complete system takeovers. And with the rise of complex, interconnected applications, the attack surface has never been larger.

This is where the OWASP Top 10 comes in. If you're not familiar with it, the Open Web Application Security Project (OWASP) is a non-profit organization that provides a ton of resources to help improve software security. Their Top 10 list is the gold standard for understanding the most critical security risks to web applications.

The 2025 list highlights some familiar foes, along with some new and evolving threats. Here's a quick rundown of some of the heavy hitters:

Broken Access Control: This is when a user can access things they shouldn't be able to. Think of a regular user being able to access an admin-only page. It’s a classic, but it still tops the charts in terms of how often it's exploited.
Cryptographic Failures: This happens when sensitive data, like passwords or credit card numbers, isn't properly protected. This could be due to weak encryption algorithms or poor key management.
Injection: This is a broad category that includes things like SQL injection & Cross-Site Scripting (XSS). Essentially, it's when an attacker can inject malicious code into your application, which then gets executed.
Insecure Design: This is a newer category that focuses on flaws in the fundamental design of your application. It's about thinking about security from the very beginning, not just as an afterthought.
Vulnerable & Outdated Components: Let's be real, we all use third-party libraries & frameworks. But if you're not keeping them up to date, you could be leaving a gaping hole in your security.

And here's a curveball for you: with the rise of AI, there's a whole new set of vulnerabilities to worry about. The OWASP Top 10 for Large Language Models (LLMs) highlights risks like prompt injection, where an attacker can manipulate the AI to do things it shouldn't, & data poisoning, where the training data for the AI is tampered with. It's a brave new world, folks.

Enter Claude Code: Your AI-Powered Security Sidekick

So, how does Claude Code fit into all of this? Think of it as a force multiplier for your security efforts. It's not just about finding vulnerabilities; it's about understanding them & fixing them, all within your natural workflow.

One of the most powerful new features is the

/security-review

command. This little gem lets you run a security analysis of your code right from your terminal. No need to switch contexts or fire up a separate tool. You just type

/security-review

, & Claude gets to work.

Here's what makes this so cool:

It's Context-Aware: Unlike traditional SAST tools that just match patterns, Claude Code has a deep, semantic understanding of your code. It doesn't just see a line of code; it understands what that code is trying to do. This means it's much better at spotting real, high-impact vulnerabilities & a lot less likely to cry wolf with a bunch of false positives.
It Explains Everything: When Claude finds a potential vulnerability, it doesn't just give you a cryptic error message. It provides a detailed explanation of what the issue is, why it's a problem, & most importantly, how to fix it. It's like having a senior security engineer walking you through the problem.
It Helps You Fix It: And here's the real magic. Once Claude has identified a vulnerability, you can actually ask it to implement the fix for you. This is HUGE. It dramatically reduces the time & effort it takes to remediate issues, so you can get back to building awesome stuff.

But it doesn't stop there. Claude Code also has a GitHub Action that automates security reviews for every pull request. This is a game-changer for teams. Once you set it up, Claude will automatically scan every new PR, flagging any potential vulnerabilities with inline comments. This creates a consistent security baseline for your entire team & ensures that no insecure code makes it to production.

Putting Claude Code to Work: A Practical Guide

Okay, that's the high-level overview. But what does this actually look like in practice? Let's walk through a few scenarios to see how you can use Claude Code to tackle some of the most common vulnerabilities.

Scenario 1: Spotting a Sneaky SQL Injection

Let's say you're working on a new feature that allows users to search for products. You've written a bit of code that takes a user's search query & uses it to build a SQL query. Here's a simplified example of what that might look like in Python: