Svelte 1.40.1 is a patch release following closely on the heels of Svelte 1.40.0, both versions of this "magical disappearing UI framework" offer developers a compelling approach to building performant web applications. The core promise of Svelte remains consistent: write declarative code that compiles away to highly efficient vanilla JavaScript at build time, resulting in smaller bundle sizes and faster runtime performance compared to traditional virtual DOM frameworks.
Examining the two versions, the devDependencies remain identical, indicating that the changes likely focused on internal bug fixes, performance tweaks, or minor adjustments to the compiler itself and not a change in the tools needed to contribute to the package. This makes the upgrade from 1.40.0 to 1.40.1 generally low-risk, meaning for developers using Svelte, 1.40.1 likely addresses some immediate issues discovered after the 1.40.0 release, contributing to a more stable and reliable experience. Given the very short time between releases, users might expect that the fixes are related to edge-cases or specific scenarios.
For developers considering Svelte, both versions represent a mature point in the framework's evolution. The rich set of development dependencies reveals the tooling ecosystem built around Svelte, encompassing linting, testing, bundling, and type checking, ensuring a well-supported and robust development workflow. With Svelte, developers can write familiar HTML, CSS, and JavaScript while benefiting from the framework's innovative compilation strategy.
All the vulnerabilities related to the version 1.40.1 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