Svelte 3.29.3 is a minor version update to the Svelte JavaScript framework, succeeding version 3.29.2. Both versions share the same core description: "Cybernetically enhanced web apps," highlighting Svelte's focus on efficiency and performance. Examining the devDependencies reveals an identical set of tools used for development and testing, including popular libraries like Rollup, TypeScript, ESLint, and Jest. This consistency suggests that the underlying development workflow and tooling remain stable between these versions.
The crucial difference lies in the dist section. While both versions have the same number of files (212), Svelte 3.29.3 shows a significantly larger unpackedSize of 5,984,428 bytes, compared to 2,441,247 bytes in Svelte 3.29.2. This suggests substantial changes within the compiled code, potentially involving bug fixes, performance improvements, or new features that expanded the overall codebase size. Developers should carefully consider this difference in size especially for projects where the application size has to be minimal, and should evaluate if the benefits of 3.29.3 overcome the extra space costs.
The release dates are also notable, with only a few minutes separating the release. Svelte 3.29.3 was released at "2020-10-22T17:29:04.200Z" and Svelte 3.29.2 at "2020-10-22T17:14:02.804Z", indicating that 3.29.3 could be a patch version released to address critical bugs found almost immediately after 3.29.2 release.
All the vulnerabilities related to the version 3.29.3 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