How severe is CVE-2026-40073?

CVE-2026-40073 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-2026-40073 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40073?

CVE-2026-40073 affects Svelte Kit. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40073?

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-2026-40073 have an EU (EUVD) identifier?

Yes. CVE-2026-40073 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21502.

When was CVE-2026-40073 published?

CVE-2026-40073 was published on 2026-04-10 and last updated on 2026-06-17.

CVE-2026-40073

CVE-2026-40073 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-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.2
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-21502
Weakness: CWE-770
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, under certain circumstances, requests could bypass the BODY_SIZE_LIMIT on SvelteKit applications running with adapter-node. This bypass does not affect body size limits at other layers of the application stack, so limits enforced in the WAF, gateway, or at the platform level are unaffected. This vulnerability is fixed in 2.57.1.

Frequently asked questions

What is CVE-2026-40073?: SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.57.1, under certain circumstances, requests could bypass the BODY_SIZE_LIMIT on SvelteKit applications running with adapter-node. This bypass does not affect body size limits at other layers of the application stack, so limits enforced in the WAF, gateway, or at the platform level are unaffected. This vulnerability is fixed in 2.57.1.
How severe is CVE-2026-40073?: CVE-2026-40073 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-2026-40073 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40073?: CVE-2026-40073 affects Svelte Kit. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40073?: 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-2026-40073 have an EU (EUVD) identifier?: Yes. CVE-2026-40073 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21502.
When was CVE-2026-40073 published?: CVE-2026-40073 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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