# CVE-2026-53721: Nuxt: Route-rule middleware bypass via case-sensitivity mismatch between vue-router and the routeRules matcher

> Attackers can bypass route-rule middleware protections in Nuxt applications due to case-sensitivity mismatches, potentially accessing restricted resources.

- **Severity:** High 8.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Jun 2026
- **Updated:** 13 Jun 2026
- **Also known as:** CLSA-2026-1784077506, CLSA-2026-1784077509, CLSA-2026-1792161453, CLSA-2026-1792161454, CLSA-2026-1792161594, CLSA-2026-1792161596, CLSA-2026-1792161816, CLSA-2026-1792161817, CLSA-2026-1792161930, CLSA-2026-1792161931, GHSA-mm7m-92g8-7m47

## What is CVE-2026-53721?

CVE-2026-53721 is a high-severity authentication bypass vulnerability in nuxt, published on 12 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Nuxt is an open-source web development framework for Vue.js. From versions 3.11.0 to before 3.21.7 and 4.0.0 to before 4.4.7, there is a route-rule middleware bypass via case-sensitivity mismatch between vue-router and the routeRules matcher. This issue has been patched in versions 3.21.7 and 4.4.7.

Weakness: CWE-863 (Incorrect Authorization), CWE-178 (Improper Handling of Case Sensitivity)

## Which versions are affected by CVE-2026-53721?

4 open source packages ship an affected version, including nuxt. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `nuxt` | npm | From 3.11.0 | 3.21.7 |
| `nuxt` | npm | From 3.11.0 | 3.21.7 |
| `nuxt` | npm | From 4.0.0 | 4.4.7 |
| `nuxt` | npm | From 4.0.0 | 4.4.7 |

Products: Nuxt Nuxt.

## How do I fix CVE-2026-53721?

Upgrade nuxt to a fixed version for your release line: 3.21.7 or 4.4.7.

## Is CVE-2026-53721 being exploited?

There is no known exploitation of CVE-2026-53721 in the wild and no public exploit code.

## Other vulnerabilities in nuxt

- [CVE-2024-23657](https://insights.sbomify.com/CVE-2024-23657/): Path Traversal: '../filedir' in Nuxt Devtools (high 8.8)
- [CVE-2024-34344](https://insights.sbomify.com/CVE-2024-34344/): Remote code execution via the browser when running the test locally in nuxt (high 8.8)
- [CVE-2024-42352](https://insights.sbomify.com/CVE-2024-42352/): Server-Side Request Forgery (SSRF) in nuxt-icon (high 8.6)
- [CVE-2023-3224](https://insights.sbomify.com/CVE-2023-3224/): Code Injection in nuxt/nuxt (high 8.1)
- [CVE-2025-27415](https://insights.sbomify.com/CVE-2025-27415/): Nuxt allows DOS via cache poisoning with payload rendering response (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53721 and fix it if it is affected.

What it is: CVE-2026-53721 is a high-severity authentication bypass vulnerability in nuxt, published on 12 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-53721 in the wild and no public exploit code.

Affected packages and fixed versions:
- nuxt (npm): affected from 3.11.0; fixed in 3.21.7
- nuxt (npm): affected from 3.11.0; fixed in 3.21.7
- nuxt (npm): affected from 4.0.0; fixed in 4.4.7
- nuxt (npm): affected from 4.0.0; fixed in 4.4.7

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-53721/ (Markdown: https://insights.sbomify.com/CVE-2026-53721/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53721
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53721
- OSV: https://osv.dev/vulnerability/CVE-2026-53721

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53721/
Summaries are generated and may contain mistakes; the official description above is the record.