CVE-2026-66062: Sveltejs Kit

Medium severity, CVSS 5.3. EPSS: 0.5% chance of exploitation in the next 30 days.

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.70.2, the content negotiation header parser used by SvelteKit's request handling (for headers such as Accept) uses a regular expression vulnerable to quadratic backtracking, so a maliciously crafted header value can cause excessive CPU consumption and degrade or deny service. Version 2.70.2 fixes the issue.

Affected products

• Sveltejs Kit: before 2.70.2 (fixed in 2.70.2)

Published 2026-08-07. Last modified 2026-09-09.