CVE-2026-44575: vercel next.js

Vulnerability summary

CVE-2026-44575 is a high (CVSS 7.5) vulnerability in vercel next.js. EPSS estimates a 0.76% chance of exploitation in the next 30 days, higher than 54.7% 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 15.2.0 to before 15.5.16 and 16.2.5, App Router applications that rely on middleware or proxy-based checks for authorization can allow unauthorized access through transport-specific route variants used for segment prefetching. In affected configurations, specially crafted .rsc and segment-prefetch URLs can resolve to the same page without being matched by the intended middleware rule, which can allow protected content to be reached without the expected authorization 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.