🚨 [security] [app] Update svelte 4.2.14 → 4.2.19 (patch)

[depfu]

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🚨 Your current dependencies have known security vulnerabilities 🚨

This dependency update fixes known security vulnerabilities. Please see the details below and assess their impact carefully. We recommend to merge and deploy this as soon as possible!

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Here is everything you need to know about this update. Please take a good look at what changed and the test results before merging this pull request.

What changed?

✳️ svelte (4.2.14 → 4.2.19) · Repo · Changelog

Security Advisories 🚨

🚨 Svelte has a potential mXSS vulnerability due to improper HTML escaping

Summary

A potential XSS vulnerability exists in Svelte for versions prior to 4.2.19.

Details

Svelte improperly escapes HTML on server-side rendering. It converts strings according to the following rules:

• If the string is an attribute value:
  • " -> "
  • & -> &
  • Other characters -> No conversion
• Otherwise:
  • < -> <
  • & -> &
  • Other characters -> No conversion

The assumption is that attributes will always stay as such, but in some situation the final DOM tree rendered on browsers is different from what Svelte expects on server-side rendering. This may be leveraged to perform XSS attacks. More specifically, this can occur when injecting malicious content into an attribute within a <noscript> tag.

PoC

A vulnerable page (+page.svelte):

<script>
import { page } from "$app/stores"
// user input

let href = $page.url.searchParams.get("href") ?? "https://example.com";

</script>
<noscript>

<a href={href}>test</a>

</noscript>

If a user accesses the following URL,

http://localhost:4173/?href=</noscript><script>alert(123)</script>

then, alert(123) will be executed.

Impact

XSS, when using an attribute within a noscript tag

🗑️ @​sveltejs/vite-plugin-svelte (removed)

🗑️ @​sveltejs/vite-plugin-svelte-inspector (removed)

🗑️ deepmerge (removed)

🗑️ svelte-hmr (removed)

🗑️ vitefu (removed)

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