CVE-2026-71321: Nuxt Unauthenticated CPU Exhaustion Parsing And Vulnerability

HIGH
Advisory Identifier: GHSA-9pgf-384g-p7mv
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CVSS 7.5
CWE-770 CWE-407
Published
Advisory Summary

CVE-2026-71321 is a HIGH (CVSS 7.5) unauthenticated cpu exhaustion parsing and vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting Nuxt libraries in the npm ecosystem. The issue involves unauthenticated cpu exhaustion parsing and hashing the nuxt island endpoint body before hash validation. Remediation is available by upgrading affected packages to version 4.5.1, 3.21.10.

CVE-2026-71321 at a Glance

CVE Identifier CVE-2026-71321
GHSA Identifier GHSA-9pgf-384g-p7mv
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product Nuxt
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-71321

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

nuxt fixed: 4.5.1 
npm install nuxt@4.5.1
nuxt fixed: 3.21.10 
npm install nuxt@3.21.10
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 nuxt

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-71321, inspect your project dependencies using npm:

npm ls nuxt

Analyze the terminal output to locate any version of Nuxt in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.5.1), your application is affected.

Note: The npm ls nuxt 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 Nuxt, 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

### Impact The internal island renderer endpoint (`/__nuxt_island/...`) decodes and hashes attacker-controlled request input before it validates the URL-resident hash. An unauthenticated `POST /__nuxt_island/<name>_<anything>.json` with a large JSON body (for example ~4.6 MB / 150k keys) is fully read, `destr`-parsed, and run through `ohash` before the request is rejected with a 400. Because Nitro runs on a single event loop, this both wastes CPU on the doomed request and delays every concurrent request. A low request rate is enough to degrade or stall the server. No valid hash and no authentication are required. ### Patches Fixed in `nuxt@4.5.1` and `nuxt@3.21.10`. The island handler now enforces a raw body-size cap (`413`) and a JSON nesting-depth cap (`400`) before parsing or hashing, so oversized or deeply nested input is rejected cheaply. ### Workarounds Put a small request-body limit in front of `/__nuxt_island/` at your reverse proxy / edge (islands legitimately send only a compact props payload), or disable server components if unused.

CVE-2026-71321 Affected Nuxt Versions

2 component(s)
Fixed Versions:
4.5.13.21.10
Product / Package Ecosystem Affected Versions Fixed Version
nuxt
npm/nuxt
npm
≥ 4.0.0
< 4.5.1
4.5.1
nuxt
npm/nuxt
npm
≥ 3.1.0
< 3.21.10
3.21.10

References

GitHub Advisory / Wiki ADVISORY
https://github.com/nuxt/nuxt/security/advisories/GHSA-9pgf-384g-p7mv
Security Fix Commit FIX COMMIT
https://github.com/nuxt/nuxt/commit/4e35ae9babd94be53246e31200232d48438bb34e
Security Fix Commit FIX COMMIT
https://github.com/nuxt/nuxt/commit/668cdfdfda41849ed11c1ee5e2067a11fc103b22
Nuxt Source Repository REPOSITORY
https://github.com/nuxt/nuxt
Nuxt Release RELEASE
https://github.com/nuxt/nuxt/releases/tag/v3.21.10
Nuxt Release RELEASE
https://github.com/nuxt/nuxt/releases/tag/v4.5.1

Frequently Asked Questions

What is CVE-2026-71321?
CVE-2026-71321 is a security vulnerability in Nuxt involving Unauthenticated CPU exhaustion parsing and hashing the Nuxt island endpoint body before hash validation under CWE-770: Allocation of Resources Without Limits or Throttling.
Which Nuxt versions are affected?
Affected versions include releases prior to 4.5.1, 3.21.10 across affected packages: nuxt.
What version fixes CVE-2026-71321?
Upgrading to 4.5.1, 3.21.10 (or the latest patched release for your respective branch) resolves the vulnerability.
Is nuxt affected?
Yes, nuxt is affected in releases prior to 4.5.1, 3.21.10. Upgrade your dependency to 4.5.1, 3.21.10 or later.
What is the CVSS score of CVE-2026-71321?
CVE-2026-71321 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-71321?
CVE-2026-71321 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-2026-71321?
Run the dependency tree command: 'npm ls nuxt'. 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-9pgf-384g-p7mv",
  "modified" : "2026-08-05T21:43:03Z",
  "published" : "2026-08-05T21:43:03Z",
  "aliases" : [ "CVE-2026-71321" ],
  "summary" : "Nuxt: Unauthenticated CPU exhaustion parsing and hashing the Nuxt island endpoint body before hash validation",
  "details" : "### Impact\n\nThe internal island renderer endpoint (`/__nuxt_island/...`) decodes and hashes attacker-controlled request input before it validates the URL-resident hash. An unauthenticated `POST /__nuxt_island/<name>_<anything>.json` with a large JSON body (for example ~4.6 MB / 150k keys) is fully read, `destr`-parsed, and run through `ohash` before the request is rejected with a 400. Because Nitro runs on a single event loop, this both wastes CPU on the doomed request and delays every concurrent request. A low request rate is enough to degrade or stall the server. No valid hash and no authentication are required.\n\n### Patches\n\nFixed in `nuxt@4.5.1` and `nuxt@3.21.10`. The island handler now enforces a raw body-size cap (`413`) and a JSON nesting-depth cap (`400`) before parsing or hashing, so oversized or deeply nested input is rejected cheaply.\n\n### Workarounds\n\nPut a small request-body limit in front of `/__nuxt_island/` at your reverse proxy / edge (islands legitimately send only a compact props payload), or disable server components if unused.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "nuxt"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.5.1"
      } ]
    } ]
  }, {
    "package" : {
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      "name" : "nuxt"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.1.0"
      }, {
        "fixed" : "3.21.10"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/nuxt/nuxt/security/advisories/GHSA-9pgf-384g-p7mv"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nuxt/nuxt/commit/4e35ae9babd94be53246e31200232d48438bb34e"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nuxt/nuxt/commit/668cdfdfda41849ed11c1ee5e2067a11fc103b22"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/nuxt/nuxt"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nuxt/nuxt/releases/tag/v3.21.10"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nuxt/nuxt/releases/tag/v4.5.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-407", "CWE-770" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-05T21:43:03Z",
    "nvd_published_at" : null
  }
}