PT-2026-4849 · Npm · Svelte

Published

2026-01-16

·

Updated

2026-01-16

CVSS v4.0

8.4

High

VectorAV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:L/VA:N/SC:H/SI:H/SA:N

Summary

A server-side rendered <textarea> with two-way bound value does not have its value correctly escaped in the rendered HTML.

Details

In SSR, <textarea bind:value={...}> does not have its value escaped when it is rendered into the HTML as <textarea>...</textarea>.

PoC

Put this in a server-side-rendered Svelte component:
<script>
 let value = `test'"></textarea><script` + `>alert('BIM');</sc` + `ript>`;
</script>

<textarea bind:value />

Impact

  • Only affects SSR
  • Needs a <textarea bind:value> filled by user content via two-way binding

Fix

XSS

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Weakness Enumeration

CWE-79

Related Identifiers

GHSA-GW32-9RMW-QWWW

Affected Products

Svelte