Svelte version 3.38.2 arrived shortly after 3.38.1, both iterations of the popular JavaScript compiler that transforms declarative components into highly efficient vanilla JavaScript. While the core functionality remains consistent – providing a streamlined development experience for building performant web applications – a closer look reveals subtle distinctions that are relevant to developers.
Both versions share identical development dependencies, suggesting that the underlying tooling and build process remained stable between releases. Key tools like Rollup, TypeScript, ESLint, and various Rollup plugins continue to facilitate module bundling, type checking, code linting, and more. This consistency ensures a familiar and reliable development environment for Svelte users.
The primary difference between the two versions lies in the unpacked size of the distributed package, with version 3.38.1 weighing in slightly heavier than 3.38.2. This variance may stem from minor code optimizations, bug fixes, or adjustments to included assets; unfortunately detailed changelogs aren't present in this data and more research is needed to determine what caused the size variation. Given the proximity of the release dates, it's plausible that 3.38.2 addresses any immediate regressions or edge cases discovered in 3.38.1. Developers working with Svelte should still benefit from its core attributes in each version: a component-based architecture encouraging code reusability, reactive updates for efficient UI rendering, and a focus on generating minimal JavaScript for optimal performance.
All the vulnerabilities related to the version 3.38.2 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