Svelte version 2.7.0 introduces incremental improvements over its predecessor, version 2.6.6, refining the developer experience for this "magical disappearing UI framework." While the core functionality remains consistent, several underlying changes impact development workflows and potentially performance. Both versions utilize an extensive suite of development dependencies, ensuring code quality, efficient bundling, and robust testing. These include tools for linting (eslint), bundling (rollup), testing (mocha, jsdom), and code transformation (typescript, buble).
Examining the dist attribute, a slight decrease in the unpackedSize from 2593791 to 2568291 bytes suggests optimizations in the compiled output. The internal code might have been refactored by the team leading to more efficient generated bundles, potentially leading to faster load times in end-user applications without affecting the developer api surface. Both versions house the same number of files within the package(15).
The update from May 25th to May 28th indicates the team actively addressed potential bugs or implemented minor enhancements. While external API changes between minor versions are infrequent, developers should review the official Svelte changelog for specific details. The package also includes some facilities for testing.
For developers, these indicate a continued commitment to maintain the core values of the library - performance through compilation and ease of use. However if upgrading from an older version than 2.6.6, comprehensive testing is always recommended to ensure continuity across all application features.
All the vulnerabilities related to the version 2.7.0 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