Improper access control in Next.js - #VU130279

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Main Vulnerability Database Vulnerabilities #VU130279

Improper access control in Next.js - #VU130279

Published: May 6, 2026


Vulnerability identifier: #VU130279
CSH Severity: High
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:Amber
CVE-ID: N/A
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability: No public exploit available
Vulnerable software:
Next.js
Software vendor:
vercel

Description

The vulnerability allows a remote attacker to disclose sensitive information.

The vulnerability exists due to improper access control in WebSocket upgrade handling in the built-in Node.js server when processing crafted WebSocket upgrade requests. A remote attacker can send a specially crafted WebSocket upgrade request to disclose sensitive information.

Only self-hosted applications using the built-in Node.js server are affected; Vercel-hosted deployments are not affected.


Remediation

Install security update from vendor's website.

External links