# CVE-2026-128118: SvelteKit: Build-time server-only module import guard could fail, resulting in server secrets being statically replaced in client bundle

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 3.0.0 until 3.1.1, the build-time server-only module guard did not treat src/params.js as a client entry point even though parameter matchers can run in the browser. Server-only modules imported through src/params.js could consequently enter the client bundle, where statically replaced private environment values or other server secrets could be exposed. This issue is fixed in 3.1.1.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- sveltejs / kit: >= 3.0.0, < 3.1.1 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-200, CWE-668

## Exploit evidence

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

## References

- https://github.com/sveltejs/kit/security/advisories/GHSA-m9j8-jcmv-hp69 (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/sveltejs/kit/commit/ae07803806f75b8b5662ae4ab92934ca1356fd84 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sveltejs/kit/releases/tag/@sveltejs/kit@3.1.1 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-128118; retrieved 2026-11-13; source updated 2026-11-13

Revision: d17be2ed0835f4acb9988e0117dda51fb5285fda75824c2a5e7cd3a6ad5be07b

Canonical: https://y2.dev/cve/CVE-2026-128118

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