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Fencer Intel
high 7.5

CVE-2026-71321 json

Nuxt: Unauthenticated CPU exhaustion parsing and hashing the Nuxt island endpoint body before hash validation

published 3mo ago modified 2mo ago also EUVD-2026-53658 , GHSA-9pgf-384g-p7mv

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 55%
public exploits
0
none known

Summary

Nuxt is an open-source web development framework for Vue.js. From 3.1.0 until 3.21.10 and 4.5.1, the internal island renderer endpoint `/__nuxt_island/...` decodes and hashes attacker-controlled JSON body input with destr and ohash before validating the URL-resident hash. An unauthenticated `POST /__nuxt_island/_.json` with a large JSON body is fully read, parsed, hashed, and then rejected, which wastes CPU on Nitro single event loop and delays concurrent requests. No valid hash and no authentication are required. This issue is fixed in 3.21.10 and 4.5.1.

Patch / fix

  • npm nuxt 3.21.10, 4.5.1
  • nuxt nuxt 3.21.10, 4.5.1

Is CVE-2026-71321 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
3mo ago

Exploit prediction

0.74% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
npm nuxt
>=4.0.0, <4.5.1
>=3.1.0, <3.21.10
4.5.1
3.21.10

Affected products

  • nuxt nuxt

Classification

Weakness
  • CWE-407 Inefficient Algorithmic Complexity
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of nuxt/nuxt published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.