Svelte version 1.56.2 represents a minor but potentially important update over its predecessor, 1.56.1. Both versions share the same core description as "The magical disappearing UI framework," highlighting Svelte's key feature: its ability to compile components into highly efficient vanilla JavaScript during the build process, leading to exceptional runtime performance for web applications.
Examining the devDependencies, most dependencies remain consistent across both versions. However, a notable difference lies in the rollup version. Version 1.56.2 utilizes rollup at version ^0.56.4, whereas 1.56.1 relies on rollup version ^0.48.2. This upgrade in the bundler is crucial. Rollup is used by Svelte during the compilation process, therefore, any update to it usually brings performance improvements, bug fixes, or support for new JavaScript features in the build process, directly impacting a Svelte developer's workflow. The file sizes also vary slightly, with v1.56.2 unpacked being 2407962 and the previous version being 2302953. A file size variations coupled with a rollup update usually means a change in the source code. Finally, the release dates indicate that version 1.56.2 was released just hours after 1.56.1, hinting a fix or an hotfix which is always important to keep in mind for developers that use it.
All the vulnerabilities related to the version 1.56.2 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