# CVE-2026-71321: Nuxt CPU exhaustion in island renderer endpoint

Source: https://junglewise.ai/threats/cve-2026-71321-nuxt-cpu-exhaustion-in-island-renderer-endpoint  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-05. Updated: 2026-08-05  
License: CC BY 4.0 with a link back

CVE-2026-71321 · Severity: high · CVSS 7.5 · Published 2026-08-05

Nuxt, a popular web framework, contains a vulnerability in its internal component rendering system. An attacker can send a specially crafted, large request to a specific server endpoint that forces the server to spend excessive time processing the data before realizing the request is invalid. Because the server handles tasks one at a time, this can cause the entire website to become slow or completely unresponsive for all users, even with a relatively small number of malicious requests.

Technologies: [nuxt (npm)](https://junglewise.ai/threats/technologies/nuxt). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-71321 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-71321 being exploited in the wild.

**How severe is CVE-2026-71321?** High severity, with a CVSS score of 7.5, published 5 August 2026.

**Which products and versions are affected?** nuxt (npm) SEMVER:introduced=4.0.0,fixed=4.5.1.

**Is there a fix for CVE-2026-71321?** Yes. nuxt (npm): upgrade to 4.5.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-71321 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-71321?** Check whether you run nuxt (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- nuxt (npm): upgrade to 4.5.1 or later

  ```sh
  npm install nuxt@4.5.1
  ```


## Technical details

The vulnerability exists in the internal island renderer endpoint (`/__nuxt_island/...`) which decodes and hashes attacker-controlled request input before validating the URL-resident hash. An unauthenticated attacker can send a POST request with a large JSON body (e.g., ~4.6 MB with 150k keys) which is fully read, parsed via `destr`, and processed through `ohash` before being rejected. Since the Nitro server runs on a single event loop, this synchronous processing blocks the event loop, leading to a Denial of Service (DoS) even at low request rates. The fix, available in versions 4.5.1 and 3.21.10, introduces a raw body-size cap (413) and a JSON nesting-depth cap (400) to reject oversized inputs before expensive parsing occurs.

## Affected products

- Nuxt nuxt >= 4.0.0, < 4.5.1
- Nuxt nuxt >= 3.1.0, < 3.21.10

## Identifiers

- CVE-2026-71321
- GHSA-9pgf-384g-p7mv

## Timeline

- 2026-07-27: disclosed: Initial disclosure to vendor
- 2026-08-05: advisory: GitHub Advisory published
- 2026-08-05: patched: Fixes released in versions 4.5.1 and 3.21.10

## References

- [https://api.github.com/users/dinhvaren](https://api.github.com/users/dinhvaren)
- [https://github.com/dinhvaren](https://github.com/dinhvaren)
- [https://api.github.com/users/dinhvaren/gists%7B/gist_id%7D](https://api.github.com/users/dinhvaren/gists%7B/gist_id%7D)
- [https://api.github.com/users/dinhvaren/repos](https://api.github.com/users/dinhvaren/repos)
- [https://avatars.githubusercontent.com/u/149681061?v=4](https://avatars.githubusercontent.com/u/149681061?v=4)
- [https://api.github.com/users/dinhvaren/events%7B/privacy%7D](https://api.github.com/users/dinhvaren/events%7B/privacy%7D)

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