Svelte 1.6.0 arrived hot on the heels of version 1.5.0, representing a quick iteration in the early days of this "magical disappearing UI framework". Both versions share the same core philosophy and dependencies, relying on tools like magic-string for efficient string manipulation during the compilation process that sets Svelte apart. The developer experience remains consistent, with negligible difference in using the framework itself.
Looking under the hood, the devDependencies remain largely the same, suggesting that the development environment and testing setup were stable between these releases. Tools for linting (eslint), bundling (rollup), testing (mocha, jsdom), and code coverage (nyc, codecov) were consistently employed. Similarly, the tools for source map generation and manipulation (source-map, source-map-support) and AST traversal (estree-walker) are present in both, implying continuity in debugging capabilities. This consistency ensures a smooth transition for developers upgrading from 1.5.0 to 1.6.0 and leveraging tools like rollup-plugin-buble for compatibility or rollup-plugin-commonjs to work with existing npm packages. The biggest key aspect for developers to know are the nearly identical setups. If you use version 1.5.0, you should have no problem upgrading to 1.6.0.
All the vulnerabilities related to the version 1.6.0 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