Svelte is a UI framework known for its "magical disappearing" act, meaning it shifts the workload from the browser to the compile step, resulting in highly performant and lightweight web applications. Version 1.19.1 is a minor update following 1.19.0, both sharing the same core philosophy and developer experience. Examining their metadata reveals a consistent set of development dependencies, including tools for testing (mocha, nyc, jsdom), linting (eslint), bundling (rollup), and code transformation (babel). This robust toolchain underscores Svelte's commitment to code quality and modern JavaScript practices.
The primary difference between the two versions lies in their release date and potentially very minor bug fixes or performance tweaks. Version 1.19.1 was released shortly after 1.19.0, suggesting that the update likely addresses issues discovered in the initial release. For developers, this means that while both versions offer the same fundamental features and functionalities, opting for 1.19.1 might provide a slightly more stable and refined experience. Svelte, in general, empowers developers to build reactive web applications with a component-based architecture. The framework's unique approach to compilation results in smaller bundle sizes and faster initial load times, leading to improved user experience. If you're starting a new Svelte project or looking to update an existing one, considering recent patch updates like this ensures you are working with the most stable version available.
All the vulnerabilities related to the version 1.19.1 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