🚨 [security] Update svelte 3.22.3 → 4.2.19 (major)

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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 upgrade. Please take a good look at what changed and the test results before merging this pull request.

What changed?

✳️ svelte (3.22.3 → 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

🚨 Svelte vulnerable to XSS when using objects during server-side rendering

The package svelte before 3.49.0 is vulnerable to Cross-site Scripting (XSS) due to improper input sanitization and to improper escape of attributes when using objects during SSR (Server-Side Rendering). Exploiting this vulnerability is possible via objects with a custom toString() function.

Release Notes

Too many releases to show here. View the full release notes.

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[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud