Hello everyone, hope you all are doing great! 🌟
Welcome back to my Medium series The Injection Chronicles. In the last episodes, we’ve already uncovered RCE, OS Injection, XML Injection, and Blind SQL Injection. Today, we move forward to unravel another subtle, often underestimated, yet powerful vulnerability — HTML Injection.

Let’s start with a quick story. Imagine you build a feedback form on your site. A user types:

<h1>You've been hacked!</h1>

Instead of it being shown as normal text, the website renders it as actual HTML — boom, your innocent form is now displaying hacker content. It might look harmless at first glance, but this opens the door for phishing, fake forms, or even redirecting users to malicious pages. That’s HTML Injection — sneaky, silent, and extremely dangerous.

What is HTML Injection?

HTML Injection is a web vulnerability where an attacker can inject raw HTML code into a vulnerable page. Unlike XSS (Cross-Site Scripting), which typically injects JavaScript, HTML Injection is more about injecting structural HTML…