Auth bypass in Vercel Next.js
CVE-2026-64642
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.
EPSS: 0.010 (61.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N.
Affected products
- Vercel Next.js — versions >= 16.0.0, < 16.2.11
Weakness classification (CWE)
References
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-64642?
- CVE-2026-64642 is a high-severity vulnerability in Vercel Next.js, classified under Improper Authorization. CVSS score: 8.2/10. Published 2026-07-27.
- How severe is CVE-2026-64642?
- High severity. CVSS v3 base score is 8.2 out of 10.