XSS Prevention in Vue
Vue's auto-escaping, dangers of v-html, DOMPurify for sanitization, trusted types.
XSS Prevention in Vue is a free Vue Academy lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Vue Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
What is XSS
Cross-Site Scripting (XSS) is an attack where malicious script is injected into a page and runs in another user's browser. It can steal cookies, tokens, and data. Vue protects you by default, but a few patterns reopen the door.
Vue Auto-Escapes Interpolation
Text inside mustache interpolation {{ }} is automatically HTML-escaped. A user string containing tags is rendered as harmless text, not executed.
<!-- userInput = "<script>alert(1)</script>" -->
<p>{{ userInput }}</p>
<!-- renders the literal text, no script runs -->Attribute Binding Is Safe Too
Binding with v-bind / :attr also escapes values, so injected quotes cannot break out of an attribute and inject handlers.
<div :title="userInput">Hover me</div>The v-html Danger
v-html sets innerHTML directly. It does not escape, so any markup - including scripts and event handlers - is rendered as live HTML.
<!-- DANGEROUS with untrusted input -->
<div v-html="userInput"></div>How v-html Gets Exploited
Even without a script tag, attacker HTML can run code through event-handler attributes or img onerror payloads.
// attacker-supplied value
const userInput = "<img src=x onerror=stealCookies()>";Rule: Never v-html User Input
The simplest rule is to never pass untrusted content to v-html. Use plain interpolation, which escapes, whenever the source is user-controlled.
When You Must Render HTML
Sometimes you genuinely need rich HTML (a CMS body, markdown output). In that case you must sanitize the HTML before binding it.
Sanitizing with DOMPurify
DOMPurify strips dangerous tags and attributes while keeping safe formatting. Install it and sanitize before v-html.
npm install dompurifySanitize Then Bind
Run the value through DOMPurify.sanitize in a computed, then bind the cleaned result.
import DOMPurify from "dompurify";
import { computed } from "vue";
const safeHtml = computed(() =>
DOMPurify.sanitize(props.rawHtml)
);
// template: <div v-html="safeHtml"></div>Configuring Allowed Tags
You can restrict the allowlist so only the tags you expect survive sanitization.
DOMPurify.sanitize(html, {
ALLOWED_TAGS: ["b", "i", "em", "strong", "a", "p"],
ALLOWED_ATTR: ["href"]
});Other Sources to Distrust
Distrust URLs too: a javascript: href in a bound link can execute. Validate or sanitize hrefs and never build dynamic <script> sources from user data.
// reject dangerous protocols
const safe = /^https?:/.test(url) ? url : "#";Quick Check
You must render user-submitted HTML. What is the safe approach?
Recap
Vue auto-escapes {{ }} interpolation and attribute bindings, neutralizing most XSS. The dangerous exception is v-html, which renders raw HTML. Never pass user input to it directly; when rich HTML is required, sanitize with DOMPurify first and also distrust user-supplied URLs.
Frequently asked questions
Is the “XSS Prevention in Vue” lesson free?
Yes — the full text of “XSS Prevention in Vue” is free to read here on the web, and the Vue Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Vue Academy course, upgrade to CoddyKit PRO.
What will I learn in “XSS Prevention in Vue”?
Vue's auto-escaping, dangers of v-html, DOMPurify for sanitization, trusted types. You practise Vue Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Vue Academy?
No prior experience is required. Vue Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “XSS Prevention in Vue” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Vue Academy lesson?
Yes. Every Vue Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.