Svelte 3.12.0 introduces subtle but important improvements over its predecessor, version 3.11.0, enhancing the developer experience and overall library performance. Examining the package.json data, the core dependencies remain largely consistent, suggesting incremental refinements rather than a major overhaul. While the listed devDependencies are identical, indicating no significant changes in the tooling or build process, the dist object reveals a slight increase in both fileCount (from 196 to 197) and unpackedSize (from 2818392 to 2832603 bytes). This suggests that Svelte 3.12.0 includes either a new file or modifications to existing files, contributing to a slightly larger overall package size.
For developers, these changes likely represent bug fixes, performance optimizations, or minor feature additions that refine the Svelte development workflow. The increased unpackedSize indicates a more robust or feature-rich library, potentially offering enhanced capabilities in areas such as component reactivity, template compilation, or runtime behavior. While the exact nature of these improvements isn't explicitly detailed in the package.json, moving to the newest version ensures developers are using the most up-to-date and potentially most performant version of the Svelte framework. Keep an eye on the official release notes to understand the specific improvements made in the version and if there are API or behavior breaking changes from older versions of the software, even if that seems very unlikely.
All the vulnerabilities related to the version 3.12.0 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