Authentication bypass using an alternate path or channel in Next.js - CVE-2026-45109
Published: May 11, 2026
Vulnerability identifier: #VU130998
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: CVE-2026-45109
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 sensitive information.
The vulnerability exists due to authentication bypass using an alternate path or channel in middleware.ts with Turbopack when handling segment-prefetch routes. A remote attacker can send a specially crafted request to disclose sensitive information.
The issue is an incomplete fix follow-up for the previously reported segment-prefetch route bypass in App Router applications.
Remediation
Install security update from vendor's website.