Svelte version 1.56.0 introduces minor improvements and bug fixes over the previous stable version, 1.55.1, making it a recommended upgrade for developers already using Svelte. Both versions share the same core development dependencies, including tools for testing (mocha, nyc, jsdom), linting (eslint), bundling (rollup), and TypeScript support. This consistency ensures a familiar development environment for those transitioning between versions.
While the core functionality remains largely consistent, subtle changes contribute to overall stability and performance. Notably, the unpackedSize of the package has decreased slightly in 1.56.0, suggesting potential optimizations in the codebase that may lead to marginal improvements in build times or runtime performance. Developers should thoroughly test the new version for any unexpected behavior in their specific applications, although the minor version bump suggests backwards compatibility is maintained.
The release dates indicate a rapid development cycle for Svelte, highlighting the project's active maintenance and commitment to improvement. Users are encouraged to review the detailed changelog for 1.56.0 to understand the specific fixes and enhancements included in this release, ensuring a smooth and optimized development experience with Svelte. These ongoing efforts solidify Svelte's position as a leading choice for building performant web applications.
All the vulnerabilities related to the version 1.56.0 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