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

 

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

Published: March 17, 2026


Vulnerability identifier: #VU124059
CSH Severity: Low
CVSS v4: 2.3 [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]
CVE-ID: CVE-2026-27977
CWE-ID: CWE-1385
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

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.


Affected software

Next.js

How to mitigate CVE-2026-27977

Install updates from vendor's website.

Next.js - update to 16.1.7

External References

Related Security Bulletins