CVE-2026-40074

SvelteKit's invalidated redirect in handle hook causes Denial-of-Service

HIGH
7.5
CVSS Score
Published: April 10, 2026 at 04:26 PM UTC
Updated: October 26, 2026 at 09:10 PM UTC
2 products affected across 2 vendorsKitKit

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.57.1
v < 2.57.1
Affected range stops below 2.57.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-755

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