# CVE-2026-114063: SvelteKit path traversal in vite preview server on Windows

Source: https://junglewise.ai/threats/cve-2026-114063-sveltekit-sveltejs-kit-from-2-10-0-before-3-0-0-contains-a-path  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-21. Updated: 2026-10-21  
License: CC BY 4.0 with a link back

CVE-2026-114063 · Severity: high · CVSS 7.5 · Published 2026-10-21

SvelteKit is a framework that developers use to build web applications. The preview server (vite preview), a tool developers run locally to test their application before deployment, contains a vulnerability on Windows that allows attackers to read sensitive files like source code, configuration files, or credentials from the server. An attacker with network access to the preview server can exploit this without authentication.

Technologies: [SvelteKit](https://junglewise.ai/threats/technologies/sveltekit). Vendors: [Svelte](https://junglewise.ai/threats/vendors/svelte).

## Quick answers

**Is CVE-2026-114063 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-114063 being exploited in the wild.

**How severe is CVE-2026-114063?** High severity, with a CVSS score of 7.5, published 21 October 2026.

**Which products and versions are affected?** SvelteKit 2.10.0 to before 3.0.0.

**Is there a fix for CVE-2026-114063?** Yes: fixed in 3.0.0. Until then: Prevent untrusted clients from accessing the preview server by keeping it bound to localhost and avoiding the --host flag or preview.host configuration on untrusted networks. Remove any public tunnels and restrict network access as appropriate. Alternatively, run the preview server on a non-Windows operating system. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-114063 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-114063?** Check whether you run SvelteKit at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 3.0.0

Prevent untrusted clients from accessing the preview server by keeping it bound to localhost and avoiding the --host flag or preview.host configuration on untrusted networks. Remove any public tunnels and restrict network access as appropriate. Alternatively, run the preview server on a non-Windows operating system.

## Technical details

A path traversal vulnerability (CWE-22) exists in SvelteKit's vite preview server on Windows in versions 2.10.0 through 2.x, introduced in 2.10.0. Unauthenticated attackers with network access can send specially crafted requests to traverse directory restrictions and read files outside the prerendered output directory. The vulnerability affects only Windows; development servers, production adapters, and preview servers on other operating systems are not affected.

## Affected products

- Svelte SvelteKit 2.10.0 to before 3.0.0

## Timeline

- 2026-10-05: disclosed
- 2026-10-20: advisory
- 2026-10-21: patched

## References

- [https://github.com/sveltejs/kit/security/advisories/GHSA-xgrj-p7pg-6vm3](https://github.com/sveltejs/kit/security/advisories/GHSA-xgrj-p7pg-6vm3)
- [https://www.vulncheck.com/advisories/sveltekit-2.10.0-before-3.0.0-path-traversal-via-vite-preview-on-windows](https://www.vulncheck.com/advisories/sveltekit-2.10.0-before-3.0.0-path-traversal-via-vite-preview-on-windows)

## Related threats

- [SvelteKit open redirect in enhanced form actions](https://junglewise.ai/threats/duplicate-advisory-sveltekit-before-3-0-0-open-redirect-via-enhanced-9a8dcd94)
- [SvelteKit server-side request forgery in self-fetch fallbacks](https://junglewise.ai/threats/cve-2026-114062-sveltekit-before-3-0-0-contains-a-server-side-request-forgery)
- [SvelteKit CPU exhaustion in remote form deserialization](https://junglewise.ai/threats/cve-2026-82261-sveltekit-cpu-exhaustion-in-remote-form-deserialization)
- [SvelteKit memory exhaustion in remote form deserialization](https://junglewise.ai/threats/cve-2026-82260-sveltekit-memory-exhaustion-in-remote-form-deserialization)
- [SvelteKit deserialization expansion in form remote function](https://junglewise.ai/threats/cve-2026-82259-sveltekit-deserialization-expansion-in-form-remote-function)