Is CVE-2026-66062 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-66062?

CVE-2026-66062 has a CVSS v3 severity of MEDIUM (5.3).

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CVE-2026-66062

Description

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.