CVE-2026-40073: @sveltejs/kit @sveltejs/adapter-node Has A BODY_SIZE_LIMIT Bypass Vulnerability

HIGH
Advisory Identifier: GHSA-2crg-3p73-43xp
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CWE-770
Published
Advisory Summary

CVE-2026-40073 is a HIGH @sveltejs/adapter-node has a body_size_limit bypass vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting @sveltejs/kit libraries in the npm ecosystem. The issue involves @sveltejs/adapter-node has a body_size_limit bypass. Remediation is available by upgrading affected packages to version 2.57.1.

CVE-2026-40073 at a Glance

CVE Identifier CVE-2026-40073
GHSA Identifier GHSA-2crg-3p73-43xp
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product @sveltejs/kit
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-40073

To remediate this vulnerability, upgrade all affected @sveltejs/kit dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@sveltejs/kit fixed: 2.57.1 
npm install @sveltejs/kit@2.57.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls @sveltejs/kit

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-40073, inspect your project dependencies using npm:

npm ls @sveltejs/kit

Analyze the terminal output to locate any version of @sveltejs/kit in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.57.1), your application is affected.

Note: The npm ls @sveltejs/kit command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In @sveltejs/kit, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2026-40073 Affected @sveltejs/kit Versions

1 component(s)
Fixed Versions:
2.57.1
Product / Package Ecosystem Affected Versions Fixed Version
@sveltejs/kit
npm/@sveltejs/kit
npm
< 2.57.1
2.57.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/sveltejs/kit/security/advisories/GHSA-2crg-3p73-43xp
NVD — CVE-2026-40073 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40073
Security Fix Commit FIX COMMIT
https://github.com/sveltejs/kit/commit/3202ed6c98f9e8d86bf0c4c7ad0f2e273e5e3b95
@sveltejs/kit Source Repository REPOSITORY
https://github.com/sveltejs/kit
@sveltejs/kit Release RELEASE
https://github.com/sveltejs/kit/releases/tag/%40sveltejs%2Fkit%402.57.1
@sveltejs/kit Release RELEASE
https://github.com/sveltejs/kit/releases/tag/@sveltejs/kit@2.57.1

Frequently Asked Questions

What is CVE-2026-40073?
CVE-2026-40073 is a security vulnerability in @sveltejs/kit involving @sveltejs/adapter-node has a BODY_SIZE_LIMIT bypass under CWE-770: Allocation of Resources Without Limits or Throttling.
Which @sveltejs/kit versions are affected?
Affected versions include releases prior to 2.57.1 across affected packages: @sveltejs/kit.
What version fixes CVE-2026-40073?
Upgrading to 2.57.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @sveltejs/kit affected?
Yes, @sveltejs/kit is affected in releases prior to 2.57.1. Upgrade your dependency to 2.57.1 or later.
What CWE is associated with CVE-2026-40073?
CVE-2026-40073 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check npm dependencies for CVE-2026-40073?
Run the dependency tree command: 'npm ls @sveltejs/kit'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2crg-3p73-43xp",
  "modified" : "2026-04-10T19:46:38Z",
  "published" : "2026-04-10T17:24:31Z",
  "aliases" : [ "CVE-2026-40073" ],
  "summary" : "@sveltejs/adapter-node has a BODY_SIZE_LIMIT bypass",
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@sveltejs/kit"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.57.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.57.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/sveltejs/kit/security/advisories/GHSA-2crg-3p73-43xp"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-40073"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sveltejs/kit/commit/3202ed6c98f9e8d86bf0c4c7ad0f2e273e5e3b95"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/sveltejs/kit"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sveltejs/kit/releases/tag/%40sveltejs%2Fkit%402.57.1"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sveltejs/kit/releases/tag/@sveltejs/kit@2.57.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-10T17:24:31Z",
    "nvd_published_at" : "2026-04-10T17:17:12Z"
  }
}