Svelte version 1.24.0 brings incremental upgrades to the "magical disappearing UI framework," building upon the foundation laid by version 1.23.4. Both versions share the same core philosophy of compiling away into highly optimized vanilla JavaScript at build time, resulting in exceptional runtime performance and a smaller bundle size for your web applications. A key area of focus in the update appears to be in the tooling and build process, leveraging updated versions of development dependencies.
Specifically, rollup has been updated from version 0.39.0 to 0.43.0. While the full impact of this rollup update would require detailed changelog analysis, it suggests potential improvements in module bundling, tree shaking, and overall build efficiency. This is important for developers because it can lead to faster build times and smaller application bundles that are deployed to production, improving user perceived performance. The updates to other dependencies like rollup-plugin-typescript are related to the main rollup update.
While many other development dependencies remain consistent between the versions, the updated rollup version indicates a push towards a modern and optimized development workflow for Svelte applications. Users upgrading should ensure compatibility with the new rollup version and take advantage of any performance improvements it offers.
All the vulnerabilities related to the version 1.24.0 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