SvelteKit: `@sveltejs/adapter-node` crashes when proxying certain requests via `fetch`

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-128123
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-13 20:18:57 UTC
Updated2026-11-13 22:14:15 UTC
DescriptionSvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. From version 5.5.7 until versions 5.5.8 and 6.0.1, , @sveltejs/adapter-node can attempt to add a header to an immutable request in a context that causes the server to crash, denying service to any other requests routed to that server. This issue is fixed in 5.5.8 and 6.0.1.

Risk And Classification

Primary CVSS: v3.1 5.9 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-248 | CWE-248 CWE-248: Uncaught Exception

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Sveltejs Kit affected >= 3.0.0-next.0, < 3.1.1 Not specified
CNA Sveltejs Kit affected < 2.70.4 Not specified
CNA @sveltejs Adapter-node affected >= 5.5.7, < 5.5.8 Not specified
CNA @sveltejs Adapter-node affected >= 6.0.0-next.0, < 6.0.1 Not specified

References

ReferenceSourceLinkTags
github.com/sveltejs/kit/commit/0a2e58cbccdd46cac20aa5af4e2edf17e0da11dd [email protected] github.com
github.com/sveltejs/kit/pull/17620 [email protected] github.com
github.com/sveltejs/kit/commit/04756a1f7a4f73e34f1934895340a46de84fc164 [email protected] github.com
github.com/sveltejs/kit/security/advisories/GHSA-rqw3-x7hx-mm3p [email protected] github.com
github.com/sveltejs/kit/releases/tag/@sveltejs/[email protected] [email protected] github.com
github.com/sveltejs/kit/releases/tag/@sveltejs/[email protected] [email protected] github.com
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