Origin validation error in Next.js - CVE-2026-94486
Published: October 2, 2026
Vulnerability identifier: #VU153125
CSH Severity: Medium
CVSS v4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-94486
CWE-ID: CWE-346
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive development data.
The vulnerability exists due to improper origin validation in the Model Context Protocol endpoint when handling requests from websites. A remote attacker can trick the developer into visiting a malicious website to disclose sensitive development data.
Only applications running with the development server are affected; production deployments do not serve this endpoint.
Affected software
Next.js
How to mitigate CVE-2026-94486
Install security update from vendor's website.
Next.js - update to 16.3.8