Svelte 3.42.2 is a minor release following directly after version 3.42.1 of the popular JavaScript compiler, known for building highly performant web applications. Both versions share the same core mission: to provide a "cybernetically enhanced" approach to web development by shifting much of the framework's work into a compile step. Developers can leverage Svelte to create reactive user interfaces with minimal overhead, making it suitable for projects of all sizes.
Examining the provided metadata, the key differences between the two versions appear to be quite subtle. Both versions maintain identical development dependencies, encompassing a robust suite of tools for testing, linting, bundling, and TypeScript support using libraries like Rollup, ESLint, and TypeScript. The devDependencies section shows a commitment to code quality and modern JavaScript practices. Key libraries mentioned are useful for testing (mocha, jsdom, c8), bundling (rollup), code transformation and analysis (css-tree, code-red, magic-string), and linting (@sveltejs/eslint-config). The core functionality and developer experience seem to be consistent between the releases. The key difference lies in the dist section: version 3.42.2 has a slightly larger unpacked size (6929180 bytes compared to 6921967 bytes) and a later release date. This indicates that version 3.42.2 likely includes bug fixes, performance improvements, or minor feature adjustments that differentiate it from version 3.42.1. For developers already using Svelte 3.42.1, upgrading to 3.42.2 is recommended to benefit from these incremental improvements.
All the vulnerabilities related to the version 3.42.2 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