Main Vulnerability Database Vulnerabilities #VU124059

Missing Origin Validation in WebSockets in Next.js - CVE-2026-27977

Published: March 17, 2026

Vulnerability identifier: #VU124059

CSH Severity: Low

CVSS v4.0: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:U/U:Clear

CVE-ID: CVE-2026-27977

CWE-ID: CWE-1385

Exploitation vector: Remote access

Exploit availability: No public exploit available

Vendor: vercel

Affected software:
Next.js

Detailed vulnerability description

The vulnerability allows a remote attacker to perform CSRF attacks.

The vulnerability exists due to incorrect handling of "Origin: null". A remote attacker can bypass dev HMR websocket CSRF checks.

Install updates from vendor's website.