SvelteKit is vulnerable to denial of service and possible SSRF when using prerendering
Summary
Versions of SvelteKit are vulnerable to a server side request forgery (SSRF) and denial of service (DoS) under certain conditions.
Details
Affected versions from 2.44.0 onwards are vulnerable to DoS if:
- your app has at least one prerendered route (
export const prerender = true)
Affected versions from 2.19.0 onwards are vulnerable to DoS and SSRF if:
- your app has at least one prerendered route (
export const prerender = true) - AND you are using
adapter-nodewithout a configuredORIGINenvironment variable, and you are not using a reverse proxy that implements Host header validation
Impact
The DoS causes the running server process to end.
The SSRF allows access to internal services that can be reached without authentication when fetched from SvelteKit's server runtime.
It is also possible to obtain an SXSS via cache poisoning, by forcing a potential CDN to cache an XSS returned by the attacker's server (the latter being able to specify the cache-control of their choice).
Credits
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @sveltejs/adapter-node | >= 5.4.1, < 5.5.1 | 5.5.1 |
| npm package | @sveltejs/kit | >= 2.19.0, < 2.49.5 | 2.49.5 |
References
- https://github.com/sveltejs/kit/security/advisories/GHSA-j62c-4x62-9r35
- https://nvd.nist.gov/vuln/detail/CVE-2025-67647
- https://github.com/sveltejs/kit/commit/d9ae9b00b14f5574d109f3fd548f960594346226
- https://github.com/sveltejs/kit
- https://github.com/sveltejs/kit/releases/tag/%40sveltejs%2Fadapter-node%405.5.1
- https://github.com/sveltejs/kit/releases/tag/%40sveltejs%2Fkit%402.49.5
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:H/SC:L/SI:L/SA:N- Weakness (CWE)
CWE-248, CWE-400, CWE-918- Platform
- npm
- Package
@sveltejs/adapter-node, @sveltejs/kit- Disclosed
- 15.01.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-j62c-4x62-9r35 - CC BY 4.0
Vulnerability history: @sveltejs/kit
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
- 17
- First → latest
- 04.2023 08.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 6
- Medium 8
- Low 3
Disclosures per year
- 2023: 2
- 2024: 3
- 2025: 1
- 2026: 11
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SvelteKit is vulnerable to denial of service and possible SSRF when using prerendering this entry
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