GitHub Advisoryadvisory · npm
GHSA-gw32-9rmw-qwww svelte is vulnerable to XSS with textarea bind:value
HIGH
Official page ↗
- Ecosystem
- npm
- Packages
- svelte
- Severity
- High
- 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
- Weaknesses
- CWE-79
- Reviewed
- 2026-01-16
Affected packages
• npm svelte: >= 3.0.0, < 3.59.2 → fixed in 3.59.2
Description
Summary
A server-side rendered `` with two-way bound value does not have its value correctly escaped in the rendered HTML.
Details
In SSR, `` does not have its value escaped when it is rendered into the HTML as `...`.
PoC
Put this in a server-side-rendered Svelte component:
```
let value = `test'">alert('BIM');`;
```
Impact
• Only affects SSR
• Needs a `` filled by user content via two-way binding
Related
Weakness · CWE (1)
- CWE-79 Improper Neutralization of Input During Web Page Generation weakness