CVE-2026-64642
Received Received - Intake

Authentication Bypass in Next.js App Router with Turbopack

Publication date: 2026-07-27

Last updated on: 2026-07-27

Assigner: GitHub, Inc.

Description
Next.js is a React framework for building full-stack web applications. In versions 16.0.0 through 16.2.10, crafted requests targeting Next.js applications using App Router built with Turbopack and a single entry in config.i18n.locales can bypass middleware/proxy based authentication. This issue has been fixed in version 16.2.11.

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Meta Information

Published
2026-07-27
Last Modified
2026-07-27
Generated
2026-07-27
AI Q&A
2026-07-27
EPSS Evaluated
N/A
NVD
CVE-2026-64642
EUVD
EUVD-2026-49382

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
vercel next.js From 16.0.0 (inc) to 16.2.10 (inc)
vercel next.js 16.2.11
vercel next.js From 16.0.0 (inc) to 16.2.11 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-285 The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.

Attack-Flow Graph

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Executive Summary

This vulnerability affects Next.js applications using the App Router with Turbopack and a single locale configuration. Crafted requests can bypass middleware or proxy-based authentication mechanisms in versions 16.0.0 through 16.2.10. The issue was fixed in version 16.2.11.

Detection Guidance

This vulnerability affects Next.js applications using App Router with Turbopack and a single locale configuration. Detection requires checking the Next.js version and configuration. Run 'npm list next' or 'yarn list next' to verify if your version is between 16.0.0 and 16.2.10. Inspect config.i18n.locales in your Next.js config file to confirm a single locale setup.

Impact Analysis

The vulnerability allows remote attackers to bypass authentication, potentially gaining unauthorized access to sensitive information. It requires no privileges or user interaction and has low attack complexity. Applications using Turbopack with single locale i18n configurations are at risk.

Mitigation Strategies

Upgrade Next.js to version 16.2.11 or later immediately. If immediate upgrade is not possible, implement server-side authorization checks in page data paths as a workaround. Avoid relying solely on middleware for authentication until patched.

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