Svelte 1.29.0 and 1.28.1 are minor version updates of the Svelte UI framework, both released in early August 2017. Svelte, known for its "magical disappearing UI framework" description, compiles your code to highly efficient vanilla JavaScript at build time, resulting in exceptional runtime performance for web applications. Both versions share the same core development dependencies, ensuring a consistent development experience. These dependencies include crucial tools like Rollup for bundling, TypeScript for type checking, ESLint for code linting, and Prettier for code formatting. This indicates a strong emphasis on code quality and maintainability within the Svelte project. Key utilities like magic-string for manipulating strings and estree-walker for traversing JavaScript syntax trees are also present, showcasing under-the-hood tooling that likely aids in Svelte's compilation process.
The primary difference between the versions lies in the fact that version 1.29.0 was released a couple of days after 1.28.1. This likely includes bug fixes and minor performance improvements. For developers, the consistent "devDependencies" between the versions means upgrading should be relatively painless, with no major breaking changes anticipated in the build or development workflow. Anyone currently using 1.28.1 should consider upgrading to take advantage of fixes and small improvements.
All the vulnerabilities related to the version 1.29.0 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