Svelte 3.44.3 is a minor update to the popular Svelte JavaScript framework, building upon version 3.44.2. Both versions share the core "Cybernetically enhanced web apps" description and maintain the same suite of developer dependencies, including tools like Rollup, TypeScript, and ESLint, ensuring a consistent developer experience. The primary difference lies in the internal improvements reflected in a slight increase in the unpacked size of the distribution, from 6945336 bytes in 3.44.2 to 6950600 bytes in 3.44.3. This increase likely indicates bug fixes, performance enhancements, or minor feature additions within the Svelte compiler and runtime.
While the specific changes aren't explicitly detailed here, developers can expect the update to provide a more stable and refined experience when building reactive user interfaces. Existing Svelte projects using version 3.44.2 can be safely upgraded to 3.44.3 to benefit from these enhancements without anticipating significant breaking changes, given the semantic versioning implies a patch release. Developers should consult the official Svelte changelog on GitHub for a granular list of resolved issues and implemented improvements to fully understand the update's impact on their applications. The release date difference shows that almost a month difference exists, so they probably accumulated some change logs in this period.
All the vulnerabilities related to the version 3.44.3 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