CVE-2026-44574
High
Description
Next.js is a React framework for building full-stack web applications. From 15.4.0 to before 15.5.16 and 16.2.5, applications that rely on middleware to protect dynamic routes can be vulnerable to authorization bypass. In affected deployments, specially crafted query parameters can alter the dynamic route value seen by the page while leaving the visible path unchanged, which can allow protected content to be rendered without passing the expected middleware check. This vulnerability is fixed in 15.5.16 and 16.2.5.
SeverityHigh
CVSS8.1
Exploit probability51. percentile0.6%
Product
Vercel Next.js
PublishedMay 13, 2026
First seenMay 13, 2026
Weakness typeCWE-288CWE-288
How to fix
Update
- vercel next.js15.5.16, 16.2.5 or later
- next15.5.16, 16.2.5 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| vercel next.js | 15.4.0 ≤ v < 15.5.16, 16.0.0 ≤ v < 16.2.5 | 15.5.16, 16.2.5 |
| nextnpm | 15.4.0 ≤ v < 15.5.16, 16.0.0 ≤ v < 16.2.5 | 15.5.16, 16.2.5 |
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