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@renovate renovate bot commented Jun 11, 2025

This PR contains the following updates:

Package Change Age Confidence
svelte (source) 4.2.18 -> 4.2.19 age confidence

GitHub Vulnerability Alerts

CVE-2024-45047

Summary

A potential XSS vulnerability exists in Svelte for versions prior to 4.2.19.

Details

Svelte improperly escapes HTML on server-side rendering. It converts strings according to the following rules:

  • If the string is an attribute value:
    • " -> "
    • & -> &
    • Other characters -> No conversion
  • Otherwise:
    • < -> &lt;
    • & -> &amp;
    • Other characters -> No conversion

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.

PoC

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.

Impact

XSS, when using an attribute within a noscript tag


Release Notes

sveltejs/svelte (svelte)

v4.2.19

Compare Source

Patch Changes
  • fix: ensure typings for <svelte:options> are picked up (#​12902)

  • fix: escape < in attribute strings (#​12989)


Configuration

📅 Schedule: Branch creation - "" in timezone Europe/London, Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

Rebasing: Never, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.


  • If you want to rebase/retry this PR, check this box

This PR was generated by Mend Renovate. View the repository job log.

@renovate renovate bot changed the title chore(deps): update dependency svelte to v4.2.19 [security] chore(deps): update dependency svelte to v4.2.19 [security] - autoclosed Jul 14, 2025
@renovate renovate bot closed this Jul 14, 2025
@renovate renovate bot deleted the renovate/npm-svelte-vulnerability branch July 14, 2025 09:43
@renovate renovate bot changed the title chore(deps): update dependency svelte to v4.2.19 [security] - autoclosed chore(deps): update dependency svelte to v4.2.19 [security] Jul 15, 2025
@renovate renovate bot reopened this Jul 15, 2025
@renovate renovate bot force-pushed the renovate/npm-svelte-vulnerability branch from 36bb2e1 to fa95e58 Compare July 15, 2025 08:11
@renovate renovate bot changed the title chore(deps): update dependency svelte to v4.2.19 [security] chore(deps): update dependency svelte to v4.2.19 [security] - autoclosed Sep 17, 2025
@renovate renovate bot closed this Sep 17, 2025
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