CVE-2026-44574: vercel next.js

Vulnerability summary

CVE-2026-44574 is a high (CVSS 8.1) vulnerability in vercel next.js. EPSS estimates a 0.67% chance of exploitation in the next 30 days, higher than 51.2% of scored vulnerabilities.

Timeline

1. 13-05-2026
   PublishedVulnerability first disclosed.
2. 13-08-2026
   Last modifiedVulnerability information updated.

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.

• CWE-288Authentication Bypass Using an Alternate Path or ChannelThe product requires authentication, but the product has an alternate path or channel that does not require authentication.
• CWE-551Incorrect Behavior Order: Authorization Before Parsing and CanonicalizationIf a web server does not fully parse requested URLs before it examines them for authorization, it may be possible for an attacker to bypass authorization protection.