Executive Summary

Security researchers at JFrog have disclosed a critical remote code execution (RCE) vulnerability, CVE-2025-11953, in the @react-native-community/cli NPM package, a core tool for the React Native framework. With a CVSS score of 9.8 and over two million weekly downloads, this flaw poses a significant threat to a vast number of software developers. The vulnerability allows an unauthenticated attacker on the same network to execute arbitrary commands on a developer's workstation. This type of compromise is particularly dangerous as it can serve as an entry point for a supply chain attack, where malicious code is injected into legitimate software. Meta, the maintainer of React Native, has issued a patch and developers must take immediate action.

Vulnerability Details

The vulnerability exists in the Metro development server, which is part of the React Native CLI toolchain. An attacker can exploit this flaw by sending a specially crafted POST request to the development server. This request can trigger the execution of arbitrary operating system commands on the host machine (the developer's computer).

The severity is compounded by a related issue in React Native's core code that could, under certain configurations, expose the development server to external networks, not just the local network. This dramatically widens the attack surface from a local exploit to a potentially remote one. The exploit has been demonstrated to work across all major operating systems: Windows, macOS, and Linux.

Affected Systems

The vulnerability affects the following versions of the @react-native-community/cli-server-api package:

• Versions 4.8.0 through 20.0.0-alpha.2

Developers using any version within this range in their projects are vulnerable.

Exploitation Status

JFrog developed a proof-of-concept (PoC) to demonstrate the vulnerability's exploitability. While there are no public reports of this flaw being exploited in the wild yet, the public disclosure and high severity make it a prime target for threat actors. Developer machines are high-value targets, and attackers are likely to begin scanning for exposed Metro servers immediately.

Impact Assessment

A successful exploit of CVE-2025-11953 could be catastrophic:

• Source Code Theft: Attackers can steal proprietary source code, API keys, and other sensitive credentials stored on the developer's machine.
• Supply Chain Attack: The attacker could inject malicious code into the application being developed. This malicious code would then be signed and distributed to end-users as part of a legitimate software update, creating a widespread supply chain incident.
• Lateral Movement: The compromised developer machine can be used as a beachhead to move laterally within the corporate network, leading to a much larger breach.

Detection Methods

1. Dependency Scanning: Use NPM or Yarn commands (npm ls @react-native-community/cli-server-api or yarn why @react-native-community/cli-server-api) or dedicated Software Composition Analysis (SCA) tools to check project dependencies for vulnerable versions.
2. Network Monitoring: Monitor for unexpected inbound POST requests to the Metro development server, which typically runs on port 8081. Any connections from untrusted or external IP addresses should be investigated.

Remediation Steps

1. Update Dependencies: The primary mitigation is to update the @react-native-community/cli-server-api package to a patched version (20.0.0 or later). Developers should run npm update or yarn upgrade to pull in the latest versions and rebuild their package-lock.json or yarn.lock files.
2. Bind to Localhost (Workaround): For those unable to update immediately, JFrog recommends ensuring the development server is bound exclusively to localhost. This prevents it from being accessible from the external network, limiting the attack surface to local-only threats. This can be configured in the project settings and is a crucial hardening step. This is an example of D3FEND's Application Configuration Hardening.