XSS attacks in React apps and how to prevent them.

Abhishek Gangwar
3 min readApr 14, 2024
Photo by Max Bender on Unsplash

Hey there, fellow tech enthusiasts! Today, we’re diving into a topic that might send a chill down your spine: XSS attacks in React. You might be thinking, “What on earth is XSS, and why should I care?” Well, buckle up, because we’re about to uncover the hidden dangers lurking in the world of web development.

Picture this: you’re happily coding away on your React application, creating beautiful user interfaces and seamless interactions. But behind the scenes, there’s a sinister threat waiting to strike — XSS, short for Cross-Site Scripting. Sounds ominous, right? That’s because it is.

What exactly is XSS?

In simple terms, it’s a type of security vulnerability that allows attackers to inject malicious scripts into web pages viewed by other users. These scripts can steal sensitive information, hijack user sessions, or even deface your website.

Now you might be thinking that —

Doesn’t React automatically prevent this?

Well, yes and no. while frameworks like React offer tools to mitigate XSS risks, they’re not foolproof shields and can be easily bypassed if we don’t understand how these work behind the scenes.

Developers need to leverage these features wisely, knowing they’re not bulletproof. Vigilance and skilful application of these capabilities are key to fortifying our apps against XSS threats.

How to Prevent XSS Attacks in React?

To prevent cross-site scripting (XSS) attacks in React, you can use the following techniques:

1 — Avoid using dangerouslySetInnerHTML:

As mentioned earlier, this method allows injecting raw HTML into your components, bypassing React’s built-in XSS protection mechanisms. Use it sparingly and only if you are certain that the HTML content is safe and sanitized.

2 — Sanitize user inputs

Always sanitize any user-generated content before rendering it in your React components. Libraries like DOMPurify can help ensure that the content is safe to render.

3 — Escape HTML entities

Use libraries like lodash.escape or a simple regEx to escape HTML entities in user inputs before rendering them. This prevents any malicious scripts from being executed.

4 — Use JSX for rendering

JSX automatically escapes any values embedded within curly braces {}. This ensures that data rendered using JSX is automatically sanitized.

5 — Content Security Policy (CSP)

Implement a strict Content Security Policy for your web application. CSP allows you to define a whitelist of trusted sources for content, scripts, and other resources. It can help mitigate the impact of XSS attacks by preventing the execution of scripts from unauthorized sources.

6 — HTTPOnly cookies:

Ensure that sensitive cookies, such as session tokens, are marked as HTTPOnly. This prevents them from being accessed by JavaScript, reducing the risk of XSS attacks that attempt to steal session data.

7 — Verify any Third-party Libraries before using them

Verify any third-party libraries before you use them inside your code base. Third-party libraries might contain vulnerabilities in their codebase. These vulnerabilities could be exploited by attackers to execute malicious scripts.

Last but not least is regularly reviewing your codebase for potential security vulnerabilities, including XSS vulnerabilities. Use automated scanning tools and manual code reviews to identify and address any security issues.

I hope this helps. Until next time, happy coding.