Vulnerability in Svelte Kit
CVE-2026-40074
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (30.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 30.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Svelte Kit
- Sveltejs Kit — versions < 2.57.1
Weakness classification (CWE)
References
- github.com/sveltejs/kit/security/advisories/GHSA-3f6h-2hrp-w5wx (Vendor Advisory)
- github.com/sveltejs/kit/commit/10d7b44425c3d9da642eecce373d0c6ef83b4fcd (Patch)
- github.com/sveltejs/kit/releases/tag/@sveltejs/kit@2.57.1 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-40074?
- CVE-2026-40074 is a high-severity vulnerability in Svelte Kit, classified under Improper Handling of Exceptional Conditions. CVSS score: 7.5/10. Published 2026-04-10.
- How severe is CVE-2026-40074?
- High severity. CVSS v3 base score is 7.5 out of 10.