Svelte version 1.43.1 is a patch release following closely after version 1.43.0, both iterations of the "magical disappearing UI framework." Examining the package data, the primary difference between these versions appears to be the release date. Version 1.43.0 was released on November 25, 2017, while version 1.43.1 was released on November 27, 2017. This suggests that version 1.43.1 likely addresses a bug or minor issue discovered shortly after the initial release of 1.43.0.
For developers using Svelte, it's generally recommended to use the latest stable version to benefit from bug fixes and improvements. While the core functionality and API remain consistent between these adjacent versions, upgrading to 1.43.1 ensures you're working with the most refined and reliable iteration of the framework at that point in time.
Both versions share identical development dependencies, showcasing a robust toolchain for building and testing Svelte applications. These dependencies include tools for linting (eslint), bundling (rollup), testing (mocha, jsdom, nightmare), and TypeScript support, indicating a commitment to code quality and developer experience. The inclusion of tools like css-tree and magic-string suggests advanced capabilities for manipulating CSS and code transformations within the Svelte compiler, further optimizing application performance. Therefore if you are using version 1.43.0 it will be good to upgrade to 1.43.1.
All the vulnerabilities related to the version 1.43.1 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