CVE-2026-40074 MEDIUM

CVE-2026-40074: SvelteKit's invalidated redirect in handle hook causes Denial-of-Service

Vendor Sveltejs
Product kit
Weakness CWE-755
Published April 10, 2026
Last update April 14, 2026

CVSS base score

6.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L

What the vulnerability does

01Description

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.57.1, redirect, when called from inside the handle server hook with a location parameter containing characters that are invalid in a HTTP header, will cause an unhandled TypeError. This could result in DoS on some platforms, especially if the location passed to redirect contains unsanitized user input. This vulnerability is fixed in 2.57.1.

Key dates

02Disclosure timeline

April 10, 2026 CVE published
April 14, 2026 Record updated