Svelte version 1.49.0, released on December 16, 2017, follows closely on the heels of version 1.48.0, which was released just two days prior on December 14, 2017. Both versions maintain the core characteristics of Svelte as "the magical disappearing UI framework," emphasizing its compile-time approach that results in highly efficient and performant web applications. A close inspection reveals no explicit changes in the listed devDependencies between the two versions. This suggests that the update primarily focused on internal improvements, bug fixes, or minor enhancements rather than introducing new dependencies or upgrading existing ones for the development workflow.
For developers using Svelte, this quick succession of releases signals ongoing maintenance and a commitment to stability. While the absence of visible dependency changes might seem uneventful, it indicates that the core tooling and development environment remain consistent. Developers can likely upgrade from 1.48.0 to 1.49.0 with minimal disruption. The focus on internal improvements means potentially better performance, fewer bugs, and refined features without requiring extensive code modifications in existing projects. Users are encouraged to consult the official Svelte changelog or release notes for a detailed breakdown of specific fixes and enhancements included in version 1.49.0 to fully leverage the benefits of the update. These incremental updates are essential for a framework's long-term health and the overall developer experience.
All the vulnerabilities related to the version 1.49.0 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