# CVE-2026-128123: SvelteKit: `@sveltejs/adapter-node` crashes when proxying certain requests via `fetch`

Status: published. Published: 2026-11-13. Updated: 2026-11-13.

SvelteKit 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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- sveltejs / kit: >= 3.0.0-next.0, < 3.1.1 (affected); < 2.70.4 (affected). Source: CNA: GitHub_M
- @sveltejs / adapter-node: >= 5.5.7, < 5.5.8 (affected); >= 6.0.0-next.0, < 6.0.1 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 5.9 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-248

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/sveltejs/kit/security/advisories/GHSA-rqw3-x7hx-mm3p (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/sveltejs/kit/pull/17620 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sveltejs/kit/commit/04756a1f7a4f73e34f1934895340a46de84fc164 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sveltejs/kit/commit/0a2e58cbccdd46cac20aa5af4e2edf17e0da11dd (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sveltejs/kit/releases/tag/@sveltejs/adapter-node@5.5.8 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sveltejs/kit/releases/tag/@sveltejs/adapter-node@6.0.1 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-128123; retrieved 2026-11-13; source updated 2026-11-13

Revision: c6b377317240fd37b05dfccb86383b99dbe4c8211293482b8a6a2c662987aabf

Canonical: https://y2.dev/cve/CVE-2026-128123

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