Svelte 3.18.1 represents a minor update over its predecessor, Svelte 3.18.0. Both versions share the same core description: "Cybernetically enhanced web apps," highlighting Svelte's ability to create highly performant and efficient web applications through its unique compiler-based approach. Developers will find the familiar set of development dependencies in both releases, indicating a consistent development environment.
A key difference lies within the updated code-red dependency, moving from version 0.0.31 in 3.18.0 to 0.0.32 in 3.18.1. While seemingly small, such dependency updates often incorporate bug fixes, performance improvements, or new features within that specific tool, potentially impacting the Svelte compiler's efficiency or the generated code's characteristics. The unpackedSize of the package also sees a fractional increase from 3067036 to 3067892 indicating some minimal addition in this new version. Finally, the releaseDate differentiates the two, with Svelte 3.18.1 being released on January 27, 2020, following Svelte 3.18.0's release on January 25, 2020. Developers should always consider reviewing the changelogs associated with each dependency update to fully understand the implications for their Svelte projects. This helps ensure compatibility and leverages any improvements the updates provide.
All the vulnerabilities related to the version 3.18.1 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