CVE-2026-71321: nuxt Inefficient Algorithmic Complexity

Vulnerability summary

CVE-2026-71321 is a high (CVSS 7.5) Inefficient Algorithmic Complexity vulnerability in nuxt. EPSS estimates a 0.74% chance of exploitation in the next 30 days, higher than 53.8% of scored vulnerabilities.

Timeline

1. 05-08-2026
   PublishedVulnerability first disclosed.
2. 06-08-2026
   Last modifiedVulnerability information updated.

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.

• CWE-407Inefficient Algorithmic ComplexityAn algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
• CWE-770Allocation of Resources Without Limits or ThrottlingThe 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.