Improper access control in Next.js - #VU130281
Published: May 6, 2026
Vulnerability identifier: #VU130281
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-284
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 improper access control in middleware authorization for Pages Router data routes when handling locale-less /_next/data//.json requests. A remote attacker can send a specially crafted request to disclose sensitive information.
Only applications using the Pages Router with i18n configured and relying on middleware or proxy-based authorization for protected page data are vulnerable.
Remediation
Install security update from vendor's website.