Svelte 2.4.0, released shortly after 2.3.0, continues to refine this "magical disappearing UI framework" aimed at building highly performant web applications. Both versions share the core philosophy of shifting the workload from the browser to the compile step, resulting in smaller, faster JavaScript bundles. Examining the devDependencies highlights subtle but potentially impactful changes for developers.
Notably, Svelte 2.4.0 introduces tiny-glob as a development dependency, suggesting enhancements or refactoring in file system operations during the build process. This might translate to improved build times or more efficient handling of project assets. Version 2.3.0 depended on glob but it was removed in 2.4.0. While seemingly minor, such changes often reflect underlying performance optimizations or architectural improvements which indirectly benefit developers using the framework. Furthermore, fileCount and unpackedSize in the dist object are greater in the newer version, implying more code and potentially more features.
For developers considering upgrading, these dependency tweaks are less about immediate API changes and more about the ongoing evolution of the Svelte compiler itself. While the core API remains consistent between these minor versions, the underlying build process becomes more streamlined and efficient. Developers should expect comparable performance with marginal improvements and a continued focus on generating lean, optimized output. The rapid release cycle between these versions signals an active development community and an iterative improvement approach.
All the vulnerabilities related to the version 2.4.0 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