Authentication bypass using an alternate path or channel in Next.js - #VU130272
Published: May 6, 2026
Vulnerability identifier: #VU130272
CSH Severity: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: N/A
CWE-ID: CWE-288
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Next.js
Next.js
Software vendor:
vercel
vercel
Description
The vulnerability allows a remote attacker to disclose protected content.
The vulnerability exists due to authentication bypass using an alternate path or channel in middleware matchers for App Router applications when handling segment-prefetch and .rsc route variants. A remote attacker can send specially crafted segment-prefetch or .rsc requests to disclose protected content.
The issue affects applications that rely on middleware or proxy-based authorization checks for protection.
Remediation
Install security update from vendor's website.