MediumGHSA-rcqx-6q8c-2c42CVE-2026-42573

Svelte Vulnerable to XSS via DOM Clobbering of Internal Framework State

Published 14 May 2026 · Updated 9 Jun 2026

Affected package

Affected
<5.55.7
Fixed in
5.55.7
Update to the fixed version for your release line, for example:npm install svelte@5.55.7

Details

Svelte was vulnerable to DOM clobbering of its internal framework state on elements, potentially leading to XSS attacks.

You are vulnerable if all of the following is true:

  • you are using attribute spreading on a form element
  • you are using attribute spreading or allow a dynamic value for the name attribute on an input or button element within that form
  • both of these are simultaneously user-controllable
<form {...spread1}>
  <input {...spread2}>
</form>

Is GHSA-rcqx-6q8c-2c42 in any of your client repos?

Checking one package by hand is fine. Checking it across forty client projects is not. NPMscan reads the lockfiles in every GitHub repo you pick, finds each project with an affected svelte, and gives you the command that fixes it.

References

Advisory data from OSV.dev (opens OSV.dev in a new tab), refreshed daily.