CVE-2025-49596: MCP Inspector RCE Vulnerability

CVE-2025-49596 Overview

The MCP inspector is a developer tool for testing and debugging MCP servers. Versions of MCP Inspector below 0.14.1 are vulnerable to remote code execution due to lack of authentication between the Inspector client and proxy, allowing unauthenticated requests to launch MCP commands over stdio. Users should immediately upgrade to version 0.14.1 or later to address these vulnerabilities.

Critical Impact

This vulnerability allows remote code execution through unauthenticated access, significantly increasing the risk of unauthorized system control.

Affected Products

• MCP Inspector < 0.14.1

Discovery Timeline

• Not Available - Vulnerability discovered by Not Available
• Not Available - Responsible disclosure to Not Available
• Not Available - CVE CVE-2025-49596 assigned
• Not Available - Not Available releases security patch
• 2025-06-13T20:15:23.133 - CVE CVE-2025-49596 published to NVD
• 2025-07-09T21:15:27.270 - Last updated in NVD database

Technical Details for CVE-2025-49596

Vulnerability Analysis

This vulnerability arises from improper authentication mechanisms within the MCP Inspector tool, allowing remote attackers to execute arbitrary code via unverified requests over stdio. An unauthenticated user can send specially crafted MCP commands, leading to potential system control.

Root Cause

The root cause is the absence of authentication checks between the Inspector client and proxy, which permits unauthorized commands to be executed on the server side.

Attack Vector

Network-based attacks can exploit this vulnerability, as it relies on sending unauthenticated requests over a network interface.

# Example exploitation code (sanitized)
import socket

def exploit_mcp(host, port):
    # Connect to the MCP server
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.connect((host, port))
        
        # Send exploitation payload
        payload = "malicious_command"
        s.sendall(payload.encode('utf-8'))

exploit_mcp('192.168.1.1', 1234)

Detection Methods for CVE-2025-49596

Indicators of Compromise

• Unexpected network traffic to MCP servers
• Unauthorized execution logs
• Anomalous MCP commands in audit trails

Detection Strategies

Implement network monitoring to detect unusual traffic patterns and unauthorized command executions directed at MCP services. Utilize IDS/IPS solutions to flag anomalies in standard MCP protocol communications.

Monitoring Recommendations

Continuous monitoring of network logs for unauthorized access attempts and server logs for execution of unexpected commands is critical.

How to Mitigate CVE-2025-49596

Immediate Actions Required

• Upgrade MCP Inspector to version 0.14.1
• Implement network access controls to restrict access to MCP services
• Apply least privilege principles to limit execution rights

Patch Information

Ensure the latest patch is applied by upgrading to MCP Inspector 0.14.1 or later to address this vulnerability.

Workarounds

Until a patch can be applied, consider implementing network-level authentication or configuring firewalls to prohibit unauthorized access to MCP services.

# Configuration example to block unauthorized access
iptables -A INPUT -p tcp --dport 1234 -j DROP