svelte is vulnerable to XSS with textarea bind:value
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
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | svelte | >= 3.0.0, < 3.59.2 | 3.59.2 |
References
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:L/VA:N/SC:H/SI:H/SA:N- Weakness (CWE)
CWE-79- Platform
- npm
- Package
svelte- Disclosed
- 16.01.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-gw32-9rmw-qwww - CC BY 4.0
Vulnerability history: svelte
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 14
- First → latest
- 07.2022 05.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 13
Disclosures per year
- 2022: 1
- 2023: 0
- 2024: 1
- 2025: 0
- 2026: 12
-
svelte is vulnerable to XSS with textarea bind:value this entry
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