Svelte version 1.2.4 is a minor update to the "magical disappearing UI framework," following closely on the heels of version 1.2.3. Both versions share the core philosophy of compiling away into highly optimized vanilla JavaScript, resulting in incredibly performant web applications with a minimal runtime footprint. Developers will appreciate the speed and efficiency gains offered by Svelte's unique approach to UI development. Both versions rely on magic-string as a dependency for manipulating strings during the compilation process.
The primary difference between these two releases lies in bug fixes and potential minor internal improvements addressed in version 1.2.4. While the core feature set remains consistent – offering a component-based architecture, reactive statements, and seamless DOM manipulation – upgrading to 1.2.4 is recommended to benefit from any stability enhancements and refined performance optimizations introduced since 1.2.3.
Both versions boast an impressive array of developer tools, including support for ES6+ syntax, comprehensive testing capabilities (using Mocha, jsdom, and nyc), and linting via ESLint. The presence of Rollup plugins like rollup-plugin-buble, rollup-plugin-commonjs, and rollup-plugin-node-resolve highlights Svelte's commitment to providing a smooth and well-integrated development experience with popular build tools. Developers using Svelte can leverage a modern JavaScript workflow with confidence. The provided releaseDate shows that both versions are quite old so please consider using updated versions of the library.
All the vulnerabilities related to the version 1.2.4 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