CVE-2026-44574 — Next.js: Middleware / Proxy bypass through dynamic route parameter injection

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
vercel / next.js	affected >= 15.4.0, < 15.5.16; affected >= 16.0.0, < 16.2.5

CWE

CWE-288

References

https://github.com/vercel/next.js/security/advisories/GHSA-492v-c6pp-mqqv

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in Next.js. This vulnerability allows an attacker to bypass security checks in web applications that use Next.js middleware to protect specific web pages. By sending specially crafted web addresses, an attacker can access protected content without proper authorization. This could lead to unauthorized viewing of sensitive information or access to restricted features.