CVE-2026-71321: Nuxt: Unauthenticated CPU exhaustion parsing and hashing the Nuxt island endpoint body before hash validation

Description

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack vector

Network

Complexity

Low

Privileges

None

User interaction

None

Confidentiality

None

Integrity

None

Availability

High

Scope

Unchanged

Exploitation

Is it being used?

Exploit prediction (EPSS)0.7% · higher than 55% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

NU

nuxt · nuxt

>= 4.0.0, < 4.5.1; >= 3.1.0, < 3.21.10 · source: vendor