#VU119104 Deserialization of untrusted data in Next.js - CVE-2025-66478
Published: December 3, 2025 / Updated: December 9, 2025
Vulnerability identifier: #VU119104
Vulnerability risk: Critical
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Red
CVE-ID: CVE-2025-66478
CWE-ID: CWE-502
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vulnerable software:
Next.js
Next.js
Software vendor:
vercel
vercel
Description
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to insecure input validation when processing serialized data within the React's App Router. A remote non-authenticated attacker can send specially crafted HTTP request to the application and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
Note, vulnerability in the react server component is tracked as a separate vulnerability #VU119103 (CVE-2025-55182).
Remediation
Install updates from vendor's website.