CVE-2026-128121

MEDIUM 5.9

SvelteKit: Prerendered paths are interpreted as regular expressions in Vercel route config generated by @sveltejs/adapter-vercel and @sveltejs/adapter-static

CVSS Score

5.9

EPSS Score

0.0%

EPSS Percentile

0th

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to @sveltejs/adapter-vercel 6.3.5 and 7.0.2 and @sveltejs/adapter-static 3.0.11 and 4.0.1, an attacker-influenced link crawled during prerendering could be emitted into the generated Vercel routing configuration without escaping regular-expression metacharacters. The configuration could consequently interpret the path as regular-expression syntax, match unintended application paths, and expose content or behavior outside the intended path. This issue is fixed in @sveltejs/adapter-vercel 6.3.5 and 7.0.2 and @sveltejs/adapter-static 3.0.11 and 4.0.1.

CWE	CWE-116 CWE-625
Vendor	sveltejs
Product	kit
Published	Nov 13, 2026
Last Updated	Nov 13, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Affected Versions

sveltejs / kit

< 2.70.4 >= 3.0.0-next.0, < 3.1.1

@sveltejs / adapter-vercel

< 6.3.5 >= 7.0.0-next.0, < 7.0.2

@sveltejs / adapter-static

< 3.0.11 >= 4.0.0-next.0, < 4.0.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/sveltejs/kit/security/advisories/GHSA-jf9x-2fg2-hx4w github.com: https://github.com/sveltejs/kit/pull/17620 github.com: https://github.com/sveltejs/kit/commit/0a2e58cbccdd46cac20aa5af4e2edf17e0da11dd github.com: https://github.com/sveltejs/kit/commit/2ed61a6aa3ac230b89e3528654c587847d1525a0 github.com: https://github.com/sveltejs/kit/releases/tag/@sveltejs/[email protected] github.com: https://github.com/sveltejs/kit/releases/tag/@sveltejs/[email protected] github.com: https://github.com/sveltejs/kit/releases/tag/@sveltejs/[email protected] github.com: https://github.com/sveltejs/kit/releases/tag/@sveltejs/[email protected]