Svelte has released version 3.31.2, a minor update following closely on the heels of version 3.31.1. Both versions maintain the core promise of "Cybernetically enhanced web apps," providing developers with a powerful framework for building performant and reactive user interfaces. Examining the metadata, the core development dependencies remain largely identical, suggesting that the updates likely focus on bug fixes, incremental improvements, or internal refactoring rather than sweeping architectural changes.
A notable difference lies in the dist section. Version 3.31.2 now includes fileCount: 214 and unpackedSize: 6320134 compared to version 3.31.1 that has fileCount: 213 and unpackedSize: 6302926, which indicates a slight increase in the package size and file numbers of the update. This could be due to the addition of new modules, updated assets, or more verbose documentation included within the bundled package. The difference in the releaseDate also pinpoint the exact moment of the release, if there were any issue with the previous realease that was quickly re-released.
For developers, this relatively small update from 3.31.1 to 3.31.2 suggests a smooth and painless transition as most underlying APIs and core functionalities are unaffected, minimizing the risk of breaking changes. It's always a good development practice to review the official changelogs and release notes for detailed insights into specific code-level modifications and bug fixes when upgrading. Keep your eyes open for any potential vulnerabilities or unexpected behaviors discovered if you're eager to stay on the bleeding edge of innovation.
All the vulnerabilities related to the version 3.31.2 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