Svelte is a JavaScript framework that lets you write efficient web applications. Comparing versions 3.46.1 and 3.46.2 reveals subtle but important differences for developers. While both share the core description of "Cybernetically enhanced web apps" and maintain the same set of devDependencies—including tools for testing (mocha, jsdom, c8), linting (eslint), bundling (rollup), and TypeScript support—the key distinctions lie in the dist section and release date. Version 3.46.2 was released on January 14, 2022, whereas version 3.46.1 came out on January 12, 2022. The unpacked size has slightly increased from 7077913 bytes to 7078265 bytes. This indicates code improvements or fix and is important for developers that want to take advantage of the latest bugfixes. Developers utilizing Svelte should consider upgrading to version 3.46.2 to benefit from these refinement, as library upgrades are essential for the application health. Remember all libraries have dependencies and their compatibility with Svelte should be tested. Both versions are distributed under the MIT license and share the same repository, authored by Rich Harris.
All the vulnerabilities related to the version 3.46.2 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