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CVE-2025-67647

SvelteKit Denial of service and possible SSRF when using prerendering

8.4 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
Low
Availability
High

Exploit likelihood

0.52%Up 0.5 points since Jan 16, 2026
90%50%10%1%

What each source reports

CVE List Score used 8.4

SvelteKit Denial of service and possible SSRF when using prerendering

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.

Record
CVE-2025-67647
CVSS 4.0
8.4 HighCVSS: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-248, CWE-918
Updated
2026-11-02
EUVDEUVD-2026-2791 8.4

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.

Record
EUVD-2026-2791
CVSS 4.0
8.4 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:H/SC:L/SI:L/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-j62c-4x62-9r35 8.4

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-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

Record
GHSA-j62c-4x62-9r35
CVSS 4.0
8.4 HighCVSS: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-248, CWE-400, CWE-918
Updated
2026-11-02
NVD 8.4

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.

Record
CVE-2025-67647
CVSS 4.0
8.4 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:H/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Weakness
CWE-248, CWE-918
Updated
2026-11-02
OSV 8.4

SvelteKit Denial of service and possible SSRF when using prerendering

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.

Record
CVE-2025-67647
CVSS 4.0
8.4 HighCVSS: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-248, CWE-918
Updated
2026-11-02
OSVGHSA-j62c-4x62-9r35 8.4

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-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

Record
GHSA-j62c-4x62-9r35
CVSS 4.0
8.4 HighCVSS: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-248, CWE-400, CWE-918
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
@sveltejs/kit
npm
2.19.0 to 2.49.4
2.49.5
@sveltejs/adapter-node
npm
5.4.1 to 5.5.0
5.5.1
@sveltejs/kit
npm
2.19.0 up to 2.49.5
2.49.5
@sveltejs/adapter-node
npm
5.4.1 up to 5.5.1
5.5.1

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2025-67647 is a high vulnerability (CVSS 8.4) in Svelte Adapter-node, published January 15, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.52%, the 44th percentile. Fixed in @sveltejs/kit 2.49.5.

References

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