CVE-2026-4199 Overview
A command injection vulnerability has been identified in bazinga012 mcp_code_executor versions up to 0.3.0. The vulnerability exists in the installDependencies function within the src/index.ts file, allowing attackers with local access to inject and execute arbitrary system commands. The exploit has been publicly disclosed and the project maintainer has been notified through an issue report but has not yet responded.
Critical Impact
Local attackers can leverage this command injection flaw to execute arbitrary commands on the host system, potentially leading to unauthorized code execution, data manipulation, or system compromise.
Affected Products
- bazinga012 mcp_code_executor up to version 0.3.0
Discovery Timeline
- 2026-03-16 - CVE-2026-4199 published to NVD
- 2026-03-16 - Last updated in NVD database
Technical Details for CVE-2026-4199
Vulnerability Analysis
This vulnerability falls under CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), commonly known as injection vulnerabilities. The installDependencies function in src/index.ts fails to properly sanitize user-supplied input before passing it to system command execution routines. This allows an attacker with local access to craft malicious input that breaks out of the intended command context and executes arbitrary commands.
The local attack vector requirement means an attacker must already have some level of access to the system or application environment to exploit this vulnerability. However, once exploited, the command injection can lead to unauthorized operations with the privileges of the running process.
Root Cause
The root cause of this vulnerability is insufficient input validation and sanitization in the installDependencies function. When processing dependency installation requests, the function directly incorporates user-controlled data into shell commands without proper escaping or parameterization. This allows specially crafted input containing shell metacharacters to be interpreted as command syntax rather than data.
Attack Vector
The attack requires local access to the system running mcp_code_executor. An attacker can manipulate input parameters passed to the installDependencies function to inject malicious commands. The injected commands will execute with the same privileges as the mcp_code_executor process.
The vulnerability mechanism involves improper handling of dependency specification strings that are passed to the underlying package manager. By including shell metacharacters such as semicolons, backticks, or command substitution syntax within dependency names or version strings, an attacker can break out of the intended command context. For detailed technical information, see the GitHub Security Advisory and the related issue on GitHub.
Detection Methods for CVE-2026-4199
Indicators of Compromise
- Unexpected child processes spawned by the mcp_code_executor application
- Unusual command execution patterns in process logs associated with dependency installation operations
- Anomalous shell metacharacters in application input logs or dependency specification files
Detection Strategies
- Monitor process execution chains for suspicious command sequences originating from Node.js or TypeScript runtime processes
- Implement application-level logging for the installDependencies function to capture input parameters
- Deploy endpoint detection and response (EDR) solutions like SentinelOne to detect command injection attack patterns
Monitoring Recommendations
- Enable verbose logging for the mcp_code_executor application to capture all dependency installation requests
- Set up alerts for shell metacharacter patterns in application inputs
- Monitor system call activity from the application process for unexpected command execution
How to Mitigate CVE-2026-4199
Immediate Actions Required
- Review all systems running mcp_code_executor versions up to 0.3.0 and assess exposure
- Restrict local access to systems running the vulnerable application
- Apply the available patch from pull request #18
- Consider temporarily disabling the dependency installation functionality until a patched version is deployed
Patch Information
A fix has been made available through a pull request. The patch commit a94ec2fea318597646ba1c44d8e44eb1c9196d20 addresses the command injection vulnerability in the installDependencies function. Users should apply this patch or upgrade to a version that includes this fix once officially released. Additional details are available in VulDB entry #351111.
Workarounds
- Implement strict input validation for all dependency specification inputs before they reach the installDependencies function
- Run the mcp_code_executor process with minimal privileges using the principle of least privilege
- Consider sandboxing the application using containerization or other isolation mechanisms to limit the impact of potential exploitation
# Example: Run mcp_code_executor with restricted privileges
# Create a dedicated user with minimal permissions
sudo useradd -r -s /bin/false mcp_executor
# Run the application as the restricted user
sudo -u mcp_executor node /path/to/mcp_code_executor/src/index.js
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
