Description
An SSR XSS exists in async hydration when attacker‑controlled keys are passed to hydratable. The key is embedded inside a <script> block without HTML‑safe escaping, allowing </script> to terminate the script and inject arbitrary JavaScript. This enables remote script execution in users' browsers, with potential for session theft and account compromise.
This issue affects Svelte: from 5.46.0 before 5.46.3.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Svelte | Svelte | 5.46.0 – < 5.46.3 | 5.46.3 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| npm | svelte | >= 5.46.0, < 5.46.4 | 5.46.4 | GHSA-6738-r8g5-qwp3 |
References
- https://fluidattacks.com/advisories/lydian third-party-advisory
- https://github.com/sveltejs/svelte/security/advisories/GHSA-6738-r8g5-qwp3 vendor-advisory