Meta React Server Components Remote Code Execution Vulnerability

Critical Threat Advisory: This vulnerability is documented in active Ransomware campaigns. Immediate remediation required.

Technical Severity

CVSS v3.1 Metrics

CRITICAL

10 / 10

Minimal Risk Critical

Vector Specification

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Exploitation Likelihood

EPSS Prediction

58.42 %

Predictive Probability

Percentile Rank

98.1 th

Documented as more likely to be exploited than 98.1% of known CVEs.

Detection Date

Dec 05, 2025

Remediation Due

Dec 12, 2025

CISA Catalog Active

Threat Analysis

Meta React Server Components contains a remote code execution vulnerability that could allow unauthenticated remote code execution by exploiting a flaw in how React decodes payloads sent to React Server Function endpoints. Please note CVE-2025-66478 has been rejected, but it is associated with CVE-2025- 55182.

Remediation Directive

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

External Intelligence

Check for signs of potential compromise on all internet accessible REACT instances after applying mitigations. For more information, please see:

https://react.dev/blog/2025/12/03/critical-security-vulnerability-in-react-server-components

https://github.com/vercel-labs/fix-react2shell-next?tab=readme-ov-file

NVD

National Vulnerability Database

https://nvd.nist.gov/vuln/detail/CVE-2025-55182