CVE-2025-67647: SvelteKit 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-node without a configured ORIGIN environment 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 - Allam Rachid (zhero;) - Allam Yasser (inzo) - d-xuan (wednesday)
Other sources
SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.49.5, SvelteKit is vulnerable to a server side request forgery (SSRF) and denial of service (DoS) under certain conditions. From 2.44.0 through 2.49.4, the vulnerability results in a DoS when your app has at least one prerendered route (export const prerender = true). From 2.19.0 through 2.49.4, the vulnerability results in a DoS when your app has at least one prerendered route and you are using adapter-node without a configured ORIGIN environment variable, and you are not using a reverse proxy that implements Host header validation. This vulnerability is fixed in 2.49.5.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What are the impacts of CVE-2025-67647?
CVE-2025-67647 can lead to denial of service (DoS) and server side request forgery (SSRF) under specific conditions.
Which versions of SvelteKit are affected by CVE-2025-67647?
Versions of SvelteKit from 2.44.0 onwards are affected by CVE-2025-67647.
What is the recommended fix for CVE-2025-67647?
The recommended fix for CVE-2025-67647 is to update to version 5.5.1 of @sveltejs/adapter-node or version 2.49.5 of @sveltejs/kit.
Can I continue using the affected versions for my project with CVE-2025-67647?
It is not advisable to continue using the affected versions with CVE-2025-67647 due to the associated security risks.
How does CVE-2025-67647 potentially affect web applications?
CVE-2025-67647 can allow attackers to perform SSRF attacks, potentially exposing sensitive data or causing outages.