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OpenAdvisories
Medium · 5.9 CVE-2026-128122 EUVD-2026-125767GHSA-5wg4-q3ww-283h

SvelteKit: Prerendered redirect paths can inject arbitrary rules into the `_redirects` file generated by `@sveltejs/adapter-cloudflare`

Published Nov 13, 2026 · Assigned by GitHub_M

Description

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. From version 4.7.0 until versions 7.2.10 and 8.0.2, @sveltejs/adapter-cloudflare allowed an attacker-influenced link crawled during prerendering to place whitespace, control characters, wildcards, or placeholders into a prerendered redirect path. The adapter wrote those paths into the Cloudflare _redirects output without output-context validation, allowing a path to create unintended routing rules that could redirect or expose requests beyond the intended prerendered route. This issue is fixed in 7.2.10 and 8.0.2.

Affected products

VendorProductAffectedFixed
sveltejs kit >= 4.7.0, < 7.2.10, >= 8.0.0-next.0, < 8.0.2 —

Affected packages

EcosystemPackageAffectedFixedRecord
npm @sveltejs/adapter-cloudflare >= 4.7.0, < 7.2.10 7.2.10 GHSA-5wg4-q3ww-283h
npm @sveltejs/adapter-cloudflare >= 8.0.0-next.0, < 8.0.2 8.0.2 GHSA-5wg4-q3ww-283h

References