Svelte version 3.5.0 introduces incremental improvements and refinements over its predecessor, version 3.4.4, solidifying its position as a leading choice for building high-performance web applications. While both share the same core philosophy of "cybernetically enhanced web apps," a closer look reveals subtle but noteworthy differences. The newer version incorporates updates to its development dependencies, most notably introducing @typescript-eslint/parser and @typescript-eslint/eslint-plugin for enhanced TypeScript linting and parsing, promoting cleaner and more maintainable code. It also bumped eslint version.
Developers leveraging TypeScript will particularly appreciate these improvements as they facilitate a smoother and more robust development workflow. Additionally, estree-walker was updated from 0.6.0 to 0.6.1. Furthermore, there's an increase in the file count within the distributed package (187 vs 180) and a substantial increase in the unpacked size (2802KB vs 1152KB), this suggests potential internal enhancements, bug fixes, or expanded functionality that contribute to a more feature-rich developer experience.
These changes, even if seemingly minor, reflect Svelte's commitment to continuous improvement and responsiveness to the evolving needs of the web development community. Consider upgrading to version 3.5.0 for a more refined and potentially more stable development experience, especially if you're working on TypeScript projects.
All the vulnerabilities related to the version 3.5.0 of the package
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.
Svelte has a potential mXSS vulnerability due to improper HTML escaping
A potential XSS vulnerability exists in Svelte for versions prior to 4.2.19.
Svelte improperly escapes HTML on server-side rendering. It converts strings according to the following rules:
" -> "& -> &< -> <& -> &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.
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.
XSS, when using an attribute within a noscript tag