Svelte 3.12.1 is a minor patch release following closely on the heels of Svelte 3.12.0, both versions focus on providing a cybernetically enhanced approach to building web applications. Examining the package metadata reveals subtle differences between the two. Both versions share the same core description and maintain an identical set of development dependencies, suggesting that the underlying development environment and toolchain remained consistent. Key dependencies like Rollup, TypeScript, and various ESLint plugins are present in both, ensuring continued compatibility and adherence to modern web development standards.
The most notable distinctions lie in the dist section. Svelte 3.12.1 has a fileCount of 196, while 3.12.0 has 197, showing that a file was removed from the package. On the other hand, Svelte 3.12.1 shows a slightly larger unpackedSize of 2832720 compared to 3.12.0's 2832603. This could indicate minor code adjustments, bug fixes, or other internal improvements that result in a slightly larger overall footprint despite having a file removed. The releaseDate also confirms that 3.12.1 was released shortly after 3.12.0, suggesting that it addresses immediate issues or enhancements identified in the prior version. Developers should consider this release to be a bugfix or targeted fix of a specific issue present in version 3.12.0. If upgrading from an earlier version, they will benefit from the cumulative improvements of both versions.
All the vulnerabilities related to the version 3.12.1 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