Svelte 3.1.0 is a minor version update to the Svelte JavaScript framework, building upon the foundation of version 3.0.1. Both versions share the core philosophy of cybernetically enhanced web apps and are distributed under the MIT license, authored by Rich Harris. Developers familiar with Svelte will find the upgrade straightforward, with no radical changes in the development workflow.
A key difference lies in the release date, with version 3.1.0 being released on April 26, 2019, a day after version 3.0.1. While the devDependencies remain identical between the two versions, suggesting no significant tooling upgrades were required for this increment, a subtle change exists in the unpacked size of the distribution. Version 3.1.0 has an unpacked size of 1001397 bytes, slightly larger than version 3.0.1's 1001046 bytes. This indicates that bug fixes, performance improvements, or minor feature additions were incorporated into the newer version, contributing to the increase in size.. Developers should always prioritize using the latest stable version to benefit from these improvements and fixes, as they contribute to a more robust and efficient development experience. Upgrade to Svelte 3.1.0 to leverage these enhancements and continue building high-performance web applications.
All the vulnerabilities related to the version 3.1.0 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