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.

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

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). 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
```
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

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