CVE-2026-2265: Replicator npm Package RCE Vulnerability

CVE-2026-2265 Overview

An unauthenticated remote code execution (RCE) vulnerability exists in applications that use the Replicator node package manager (npm) version 1.0.5 to deserialize untrusted user input and execute the resulting object. This insecure deserialization vulnerability allows attackers to craft malicious serialized payloads that, when processed by the Replicator package, can lead to arbitrary code execution on the target system.

Critical Impact

Attackers can exploit this vulnerability to execute arbitrary code remotely without authentication, potentially compromising entire Node.js applications and underlying server infrastructure.

Affected Products

• Replicator npm package version 1.0.5
• Applications using Replicator to deserialize untrusted user input
• Node.js applications with exposed deserialization endpoints

Discovery Timeline

• April 1, 2026 - CVE-2026-2265 published to NVD
• April 1, 2026 - Last updated in NVD database

Technical Details for CVE-2026-2265

Vulnerability Analysis

The Replicator npm package is designed to serialize and deserialize JavaScript objects, enabling the transfer of complex data structures across different contexts. The vulnerability arises when the package processes untrusted user-supplied input during deserialization operations. When an application deserializes data from an untrusted source without proper validation, attackers can inject malicious payloads that get executed during the deserialization process.

This class of vulnerability is particularly dangerous in Node.js applications because JavaScript's dynamic nature allows serialized objects to contain executable code. When the Replicator package reconstructs these objects, any embedded malicious logic can be triggered, leading to remote code execution on the server.

Root Cause

The root cause of this vulnerability lies in the unsafe handling of user-controlled input during object deserialization. The Replicator package version 1.0.5 does not adequately validate or sanitize the structure of serialized data before reconstructing JavaScript objects. This allows attackers to craft payloads containing malicious object properties or prototype chains that execute arbitrary code when the object is instantiated or when specific properties are accessed.

Insecure deserialization vulnerabilities in JavaScript typically exploit prototype pollution, constructor injection, or the execution of getter/setter functions during object reconstruction.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker can exploit this vulnerability by:

1. Identifying an endpoint or functionality where the application uses Replicator to deserialize data
2. Crafting a malicious serialized payload containing code execution primitives
3. Sending the payload to the vulnerable endpoint
4. The application deserializes the payload using Replicator, triggering code execution

The exploitation does not require any special privileges, making it accessible to any network attacker who can reach the vulnerable application. Technical details and analysis are available in the Moriel Harush CVE-2026-2265 Analysis.

Detection Methods for CVE-2026-2265

Indicators of Compromise

• Unexpected child processes spawning from Node.js application processes
• Unusual network connections originating from the application server
• Suspicious entries in application logs indicating deserialization of malformed objects
• Evidence of reverse shell connections or command execution in system logs

Detection Strategies

• Monitor application dependencies using npm audit or similar tools to identify vulnerable Replicator package versions
• Implement application-level logging for all deserialization operations to capture anomalous payloads
• Deploy runtime application self-protection (RASP) solutions to detect and block deserialization attacks
• Use SentinelOne's Singularity platform to monitor for suspicious process execution chains originating from Node.js applications

Monitoring Recommendations

• Enable verbose logging for all API endpoints that accept serialized data
• Implement anomaly detection for unusual payload sizes or structures in deserialization functions
• Monitor for process creation events from Node.js workers that deviate from normal application behavior
• Track outbound network connections from application servers for potential data exfiltration or C2 communication

How to Mitigate CVE-2026-2265

Immediate Actions Required

• Audit all applications to identify usage of the Replicator npm package version 1.0.5
• Review and update the package to a patched version if available, as referenced in GitHub Pull Request #19
• Implement input validation on all endpoints that accept serialized data
• Consider removing or replacing the Replicator package with a more secure alternative if no patch is available

Patch Information

A fix for this vulnerability has been proposed in GitHub Pull Request #19 in the Replicator GitHub Repository. Organizations should monitor the repository for official releases incorporating this fix and update their dependencies accordingly.

Workarounds

• Never deserialize data from untrusted sources; implement strict input validation before processing
• Use allowlisting to restrict the types of objects that can be deserialized
• Implement Content Security Policy headers and other defense-in-depth measures to limit the impact of successful exploitation
• Isolate applications using Replicator in sandboxed environments to contain potential compromise

# Check for vulnerable Replicator version in your project
npm list replicator

# Audit npm dependencies for known vulnerabilities
npm audit

# Update to latest version when patch is available
npm update replicator