CVE-2026-6118: AstrBot Command Injection RCE Vulnerability

CVE-2026-6118 Overview

A command injection vulnerability has been identified in AstrBotDevs AstrBot versions up to 4.22.1. The vulnerability exists in the add_mcp_server function within the file astrbot/dashboard/routes/tools.py, which is part of the MCP Endpoint component. Improper handling of the command argument allows attackers to inject arbitrary operating system commands, potentially leading to unauthorized command execution on the underlying system.

Critical Impact

Remote attackers with low privileges can exploit this command injection vulnerability to execute arbitrary commands on the server, potentially compromising system integrity, confidentiality, and availability.

Affected Products

• AstrBotDevs AstrBot versions up to 4.22.1
• Systems running the AstrBot dashboard with MCP Endpoint functionality enabled

Discovery Timeline

• 2026-04-12 - CVE-2026-6118 published to NVD
• 2026-04-13 - Last updated in NVD database

Technical Details for CVE-2026-6118

Vulnerability Analysis

This command injection vulnerability (CWE-74: Injection) affects the MCP Endpoint component of AstrBot. The add_mcp_server function in astrbot/dashboard/routes/tools.py fails to properly sanitize or validate the command argument before processing it. This allows an attacker to craft malicious input that breaks out of the intended command context and executes arbitrary system commands.

The vulnerability is exploitable remotely over the network and requires low privileges to trigger. The exploit has been publicly disclosed, increasing the risk of active exploitation. Notably, the project maintainers were informed through GitHub Issue #7169 but had not responded at the time of disclosure.

Root Cause

The root cause of this vulnerability is insufficient input validation and sanitization within the add_mcp_server function. When the command argument is received from user input, it is processed without proper escaping or validation, allowing shell metacharacters and command separators to be interpreted by the underlying operating system shell. This is a classic injection flaw where user-controlled data is mixed with executable commands without proper separation.

Attack Vector

The attack vector is network-based, requiring the attacker to have authenticated access (low privileges) to the AstrBot dashboard interface. An attacker can craft a malicious request to the MCP Endpoint containing shell metacharacters (such as ;, |, &&, or backticks) within the command parameter. When the vulnerable add_mcp_server function processes this input, the injected commands are executed with the privileges of the AstrBot process.

The vulnerability mechanism involves sending crafted input to the MCP Endpoint that contains command injection payloads. For example, an attacker could append shell operators followed by malicious commands to the expected input, causing the server to execute unintended operations. Technical details regarding the specific exploitation technique can be found in the VulDB submission #792655 and VulDB entry #356978.

Detection Methods for CVE-2026-6118

Indicators of Compromise

• Unusual command execution patterns originating from the AstrBot process
• Unexpected network connections or data exfiltration from the server running AstrBot
• Anomalous entries in web server access logs targeting the MCP Endpoint routes
• Suspicious shell command sequences in process execution logs

Detection Strategies

• Monitor web application firewall (WAF) logs for requests containing shell metacharacters (;, |, &&, `, $()) targeting /dashboard/routes/tools endpoints
• Implement application-level logging to capture all inputs to the add_mcp_server function
• Deploy endpoint detection solutions to identify unusual process spawning from the AstrBot application

Monitoring Recommendations

• Configure SIEM rules to alert on command injection patterns in HTTP request parameters
• Enable detailed logging for the AstrBot dashboard component and review logs regularly
• Monitor system process trees for unexpected child processes spawned by the AstrBot service

How to Mitigate CVE-2026-6118

Immediate Actions Required

• Restrict network access to the AstrBot dashboard to trusted IP addresses only
• Implement additional authentication requirements for the MCP Endpoint functionality
• Consider disabling the MCP server functionality until a patch is available
• Apply web application firewall rules to block requests containing shell metacharacters

Patch Information

At the time of this writing, the AstrBot project maintainers have not responded to the vulnerability disclosure submitted via GitHub Issue #7169. Users should monitor the AstrBot GitHub repository for security updates and patches. Consider upgrading to versions beyond 4.22.1 once a security fix is released.

Workarounds

• Implement input validation at the reverse proxy or WAF level to sanitize the command parameter
• Deploy network segmentation to isolate the AstrBot instance from critical systems
• Apply the principle of least privilege by running AstrBot under a restricted user account
• Use containerization to limit the impact of potential command execution

# Example WAF rule to block common command injection patterns
# ModSecurity rule example
SecRule ARGS "@rx [;|&`$()]" "id:100001,phase:2,deny,status:403,msg:'Potential command injection detected'"

# Restrict access to AstrBot dashboard by IP (nginx example)
location /dashboard/ {
    allow 192.168.1.0/24;
    deny all;
}