CVE-2026-27118

Medium

Description

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Versions of @sveltejs/adapter-vercel prior to 6.3.2 are vulnerable to cache poisoning. An internal query parameter intended for Incremental Static Regeneration (ISR) is accessible on all routes, allowing an attacker to cause sensitive user-specific responses to be cached and served to other users. Successful exploitation requires a victim to visit an attacker-controlled link while authenticated. Existing deployments are protected by Vercel's WAF, but users should upgrade as soon as possible. This vulnerability is fixed in 6.3.2.

SeverityMedium
CVSS5.3
Exploit probability—
Product@sveltejs/adapter-vercel
PublishedFeb 20, 2026
First seenFeb 20, 2026
Weakness typeCWE-346CWE-346

How to fix

Update
  • @sveltejs/adapter-vercel6.3.2 or later

Affected products

ProductAffected versionsFixed in
@sveltejs/adapter-vercelnpmv < 6.3.26.3.2

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.

CVE-2026-27118 · @sveltejs/adapter-vercel · Dark Radar