Svelte version 3.40.2 is a minor release following 3.40.1, both maintaining the core promise of "Cybernetically enhanced web apps." While the core functionality remains consistent, several subtle changes differentiate the two versions, potentially impacting developers updating their projects. A primary distinction lies in the packed size and included file count; version 3.40.2 includes one additional file and a slightly larger unpacked size compared to its predecessor, suggesting possible additions, bug fixes, or internal refactoring of the package. Both versions share an identical set of development dependencies, indicating no major overhauls in the build process or testing framework. Developers leveraging Svelte should be aware of the updated release date. Svelte 3.40.2 was released a day after 3.40.1. For developers using Svelte, these incremental versions signify the project's commitment to ongoing maintenance, bug fixes, and evolutionary improvements within the established API, without introducing breaking changes.
All the vulnerabilities related to the version 3.40.2 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