Svelte version 3.6.0 offers incremental improvements over its predecessor, version 3.5.4, primarily focusing on internal build processes and dependency updates, which ultimately contribute to a more robust and efficient development experience. Examining the devDependencies, while the list appears identical, subtle underlying updates within these tools often lead to enhanced stability and performance in the generated Svelte code. For developers, this translates to potentially fewer build errors and improved runtime behavior of their Svelte applications.
A notable change lies in the dist field. Version 3.6.0 has a fileCount of 239 and an unpackedSize of 2811605, while version 3.5.4 has a fileCount of 191 and an unpackedSize of 2780322. This indicates that version 3.6.0 includes more files and has a larger unpacked size, meaning some new features, bug fixes, or internal changes were introduced to the library.
While the core functionalities and API likely remain consistent, upgrading to 3.6.0 offers users the benefits of the latest tooling and any bug fixes implemented since 3.5.4. Svelte developers should consider upgrading to harness these improvements and benefit from the continuous refinement of the Svelte compiler and associated development ecosystem, contributing to smoother development workflows and increased application reliability.
All the vulnerabilities related to the version 3.6.0 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