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CVE-2026-40073: Svelte Kit Allocation Without Limits (CVSS 8.2)

CVE-2026-40073 is a high severity allocation without limits in Svelte Kit with a CVSS score of 8.2. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Last updated: Jun 17, 2026

Quick answer

Direct answer

CVE-2026-40073 is a high severity allocation without limits in Svelte Kit with a CVSS score of 8.2. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Risk scores

CVSS base score
8.2HIGH
EPSS probability
0.95%
Higher than 61 percent of all CVEs
CISA KEV
Not listed
CVSS metricWhat it means
Attack vector (AV:N)Network: reachable remotely
Attack complexity (AC:L)Low complexity
Attack requirements (AT:P)Attack requirements present
Privileges required (PR:N)No privileges required
User interaction (UI:N)No user interaction
Confidentiality (VC:N)No confidentiality impact
Integrity (VI:N)No integrity impact
Availability (VA:H)High availability impact

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

About Svelte Kit

CVE-2026-40073 affects Svelte Kit, a product from Svelte. Before acting, confirm where Svelte Kit runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.

What the flaw is

In plain terms: 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.

The weakness class is Allocation Without Limits. Resources are allocated without a cap.

Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Affected versions and timeline

FieldDetail
ProductSvelte Kit
Affected versionsKit before 2.57.1
PublishedApr 10, 2026
Last modifiedJun 17, 2026
Added to CISA KEVNot listed
Assigning CNAsecurity-advisories@github.com

How to detect it

  • Inventory every instance of Svelte Kit and record the running version against the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
  • Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.

How to fix it

  • Apply the fixed version of Svelte Kit named in the vendor advisory.
  • If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
  • Rescan after the change to prove the exposure is gone, then close the ticket.

CTEM action plan

CTEM stageWhat to do for this CVE
ScopeAdd every business service that depends on Svelte Kit to the current CTEM cycle.
DiscoverFind all instances, including shadow and cloud deployments, and record versions and exposure.
PrioritizeRank using EPSS and CVSS together with asset exposure and business impact.
ValidateConfirm the flaw is reachable and exploitable in your environment and that compensating controls work.
MobilizeAssign the fix to the asset owner with a due date matched to the priority, then verify closure.

CWE References

Technical References

Frequently asked questions

CVE-2026-40073 is a high severity allocation without limits in Svelte Kit with a CVSS score of 8.2. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

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