# CVE-2026-128121: SvelteKit: Prerendered paths are interpreted as regular expressions in Vercel route config generated by @sveltejs/adapter-vercel and @sveltejs/adapter-static

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

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.

## Remediation

- fix: @sveltejs/adapter-vercel (npm): OSV reports a fixed version 6.3.5. Check the advisory for supported release branches. (source: OSV GHSA-jf9x-2fg2-hx4w) — https://github.com/advisories/GHSA-jf9x-2fg2-hx4w
- fix: @sveltejs/adapter-static (npm): OSV reports a fixed version 4.0.1. Check the advisory for supported release branches. (source: OSV GHSA-jf9x-2fg2-hx4w) — https://github.com/advisories/GHSA-jf9x-2fg2-hx4w
- fix: @sveltejs/adapter-vercel (npm): OSV reports a fixed version 7.0.2. Check the advisory for supported release branches. (source: OSV GHSA-jf9x-2fg2-hx4w) — https://github.com/advisories/GHSA-jf9x-2fg2-hx4w
- fix: @sveltejs/adapter-static (npm): OSV reports a fixed version 3.0.11. Check the advisory for supported release branches. (source: OSV GHSA-jf9x-2fg2-hx4w) — https://github.com/advisories/GHSA-jf9x-2fg2-hx4w

## Affected products and versions

- sveltejs / kit: < 2.70.4 (affected); >= 3.0.0-next.0, < 3.1.1 (affected). Source: CNA: GitHub_M
- @sveltejs / adapter-vercel: < 6.3.5 (affected); >= 7.0.0-next.0, < 7.0.2 (affected). Source: CNA: GitHub_M
- @sveltejs / adapter-static: < 3.0.11 (affected); >= 4.0.0-next.0, < 4.0.1 (affected). Source: CNA: GitHub_M
-  / @sveltejs/adapter-vercel (@sveltejs/adapter-vercel): ≥ 0; < 6.3.5 (affected, semver); OSV events: introduced 0; fixed 6.3.5. Source: OSV GHSA-jf9x-2fg2-hx4w
-  / @sveltejs/adapter-static (@sveltejs/adapter-static): ≥ 4.0.0-next.0; < 4.0.1 (affected, semver); OSV events: introduced 4.0.0-next.0; fixed 4.0.1. Source: OSV GHSA-jf9x-2fg2-hx4w
-  / @sveltejs/adapter-vercel (@sveltejs/adapter-vercel): ≥ 7.0.0-next.0; < 7.0.2 (affected, semver); OSV events: introduced 7.0.0-next.0; fixed 7.0.2. Source: OSV GHSA-jf9x-2fg2-hx4w
-  / @sveltejs/adapter-static (@sveltejs/adapter-static): ≥ 0; < 3.0.11 (affected, semver); OSV events: introduced 0; fixed 3.0.11. Source: OSV GHSA-jf9x-2fg2-hx4w

## Severity and prioritization

- CVSS 3.1: 5.9 (medium); CVSS:3.1/AV:N/AC:H/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: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-116, CWE-625

## Exploit evidence

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

## References

- https://github.com/sveltejs/kit/security/advisories/GHSA-jf9x-2fg2-hx4w (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/0a2e58cbccdd46cac20aa5af4e2edf17e0da11dd (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sveltejs/kit/commit/2ed61a6aa3ac230b89e3528654c587847d1525a0 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sveltejs/kit/releases/tag/@sveltejs/adapter-static@3.0.11 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sveltejs/kit/releases/tag/@sveltejs/adapter-static@4.0.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sveltejs/kit/releases/tag/@sveltejs/adapter-vercel@6.3.5 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sveltejs/kit/releases/tag/@sveltejs/adapter-vercel@7.0.2 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/advisories/GHSA-jf9x-2fg2-hx4w (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-jf9x-2fg2-hx4w (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-128121; retrieved 2026-11-13; source updated 2026-11-13

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-jf9x-2fg2-hx4w; retrieved 2026-11-13; source updated 2026-11-13

Revision: e2f80accaba3e98d0c91f0d425ef3c6cd4d3f93b07f8e2bdfa401e13f23ead39

Canonical: https://y2.dev/cve/CVE-2026-128121

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