CVE-2026-4198: mcp-server-auto-commit RCE Vulnerability

CVE-2026-4198 Overview

A command injection vulnerability has been identified in hypermodel-labs mcp-server-auto-commit version 1.0.0. The vulnerability exists in the getGitChanges function within the index.ts file, where improper input validation allows for command injection attacks. While the attack requires local access, the exploit has been publicly disclosed and may be utilized by threat actors with local system access.

Critical Impact

Local attackers can inject arbitrary commands through the vulnerable getGitChanges function, potentially leading to unauthorized command execution, data manipulation, or further system compromise.

Affected Products

• hypermodel-labs mcp-server-auto-commit 1.0.0

Discovery Timeline

• 2026-03-16 - CVE-2026-4198 published to NVD
• 2026-03-16 - Last updated in NVD database

Technical Details for CVE-2026-4198

Vulnerability Analysis

This command injection vulnerability (CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component) affects the getGitChanges function in the index.ts file of the mcp-server-auto-commit package. The vulnerability stems from insufficient input sanitization, allowing malicious input to be interpreted as executable commands by the underlying system shell.

The mcp-server-auto-commit project is designed to automatically commit changes to Git repositories. The vulnerable function processes Git-related operations without properly validating or sanitizing user-controlled input before passing it to shell commands. This creates an opportunity for attackers to inject arbitrary commands that will be executed with the privileges of the application.

Root Cause

The root cause of this vulnerability is the improper neutralization of special elements within the getGitChanges function. When processing input parameters related to Git operations, the function fails to properly escape or validate command-line arguments before passing them to shell execution functions. This allows specially crafted input containing shell metacharacters or command separators to break out of the intended command context and execute attacker-controlled commands.

Attack Vector

The attack vector requires local access to the system where mcp-server-auto-commit is installed. An attacker with local access can manipulate input to the getGitChanges function by crafting malicious Git repository paths or filenames containing shell command injection sequences.

The vulnerability mechanism involves passing unsanitized input to shell commands. When the getGitChanges function executes Git commands using shell invocation, the injected payload is interpreted and executed by the system shell. For detailed technical information, see the GitHub Issue Discussion and the Security Advisory PDF.

Detection Methods for CVE-2026-4198

Indicators of Compromise

• Unusual command executions spawned from Node.js processes running mcp-server-auto-commit
• Unexpected shell processes with suspicious command-line arguments containing special characters like ;, |, &&, or backticks
• Log entries showing malformed Git repository paths or filenames with embedded shell commands

Detection Strategies

• Monitor process execution chains for Node.js spawning unexpected child processes such as /bin/sh, /bin/bash, or other system shells
• Implement file integrity monitoring on systems running mcp-server-auto-commit to detect unauthorized modifications
• Review application logs for requests containing shell metacharacters in Git-related parameters

Monitoring Recommendations

• Deploy endpoint detection solutions to monitor for command injection attack patterns in Node.js applications
• Enable detailed logging for the mcp-server-auto-commit application to capture all input parameters
• Set up alerts for processes executing unusual commands from the context of Git automation tools

How to Mitigate CVE-2026-4198

Immediate Actions Required

• Apply the security patch identified by commit hash f7d992c830c5f2ec5749852e66c0195e3ed7fe30 immediately
• Audit systems running mcp-server-auto-commit 1.0.0 for signs of exploitation
• Restrict local access to systems running the vulnerable application until patched
• Consider temporarily disabling the mcp-server-auto-commit functionality if patching is not immediately possible

Patch Information

A patch has been made available for this vulnerability. The fix is identified by patch commit f7d992c830c5f2ec5749852e66c0195e3ed7fe30. The recommended action is to apply this patch to remediate the command injection vulnerability in the getGitChanges function. The patch can be reviewed at the GitHub Pull Request.

Note that the project maintainers were informed of this vulnerability early through an issue report but have not yet responded, so users should apply the community-provided patch independently.

Workarounds

• If patching is not immediately possible, restrict execution permissions for the mcp-server-auto-commit application to trusted users only
• Implement input validation at the application layer to filter out shell metacharacters before they reach the vulnerable function
• Run the application in a sandboxed environment with limited shell execution capabilities
• Consider using alternative Git automation tools until the official patch is confirmed and released

# Configuration example - Apply the security patch
cd /path/to/mcp-server-auto-commit
git fetch origin
git cherry-pick f7d992c830c5f2ec5749852e66c0195e3ed7fe30
npm install
npm run build