How severe is CVE-2026-40074?

CVE-2026-40074 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-40074 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40074?

CVE-2026-40074 affects Svelte Kit. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40074?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-40074 have an EU (EUVD) identifier?

Yes. CVE-2026-40074 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21504.

When was CVE-2026-40074 published?

CVE-2026-40074 was published on 2026-04-10 and last updated on 2026-06-17.

CVE-2026-40074

CVE-2026-40074 is a high-severity vulnerability in Svelte Kit with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-755.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 6.3
EPSS exploit prediction: 0% (29th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-21504
Weakness: CWE-755
Affected product: Svelte Kit
Published: 2026-04-10
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-40074?: CVE-2026-40074 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-40074 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40074?: CVE-2026-40074 affects Svelte Kit. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40074?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-40074 have an EU (EUVD) identifier?: Yes. CVE-2026-40074 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21504.
When was CVE-2026-40074 published?: CVE-2026-40074 was published on 2026-04-10 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:svelte:kit:*:*:*:*:*:node.js:*:*

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