Svelte 3.33.0 builds upon the foundation of its predecessor, version 3.32.3, offering subtle but potentially impactful refinements for developers building web applications. Both versions share the core philosophy of Svelte - delivering cybernetically enhanced web apps through a compiler that transforms components into highly efficient vanilla JavaScript. The essential developer experience remains consistent, with familiar tools and a focus on writing less code.
A notable difference lies in the unpacked size, with version 3.33.0 slightly larger, indicating potential additions or adjustments within the compiled output or internal tooling. While the core dependencies largely remain the same, any internal changes could affect performance characteristics or bug fixes applied in the newer version. Developers should examine release notes and changelogs for detailed information on these modifications.
For developers already using Svelte, upgrading to 3.33.0 offers potential benefits in terms of stability and refined performance, though a thorough testing regime is advised, particularly for complex applications. Newcomers to Svelte will find both versions to be excellent starting points, focusing on a lean and reactive component model. The shared dependency landscape ensures a familiar environment with tools such as Rollup, TypeScript, and ESLint, offering flexibility in how developers structure their projects. Choosing between the two versions hinges on project-specific needs, with 3.33.0 being the likely preferential choice due to its recency although detailed differences should be investigated before upgrading.
All the vulnerabilities related to the version 3.33.0 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