CVE-2026-108953
Received Received - Intake

OS Command Injection in mac-shell-mcp

Publication date: 2026-10-12

Last updated on: 2026-10-12

Assigner: VulnCheck

Description
mac-shell-mcp before 2.0.0 contains an OS command injection vulnerability that allows MCP clients to bypass the command whitelist by injecting shell metacharacters into execute_command arguments. Attackers or malicious prompts can call a safe command such as pwd with arguments like ';' to run forbidden commands as the server user without approval.

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Meta Information

Published
2026-10-12
Last Modified
2026-10-12
Generated
2026-10-12
AI Q&A
2026-10-12
EPSS Evaluated
N/A
NVD
CVE-2026-108953
EUVD
EUVD-2026-97360

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
cfdude mac-shell-mcp 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-78 The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

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Executive Summary

mac-shell-mcp before 2.0.0 has an OS command injection flaw where attackers can bypass command whitelists by injecting shell metacharacters like semicolons into execute_command arguments. For example, a safe command like 'pwd' can be manipulated to run unauthorized commands as the server user without approval.

Detection Guidance

Check if mac-shell-mcp versions before 2.0.0 are installed by running: npm list mac-shell-mcp. If installed, verify if the execute_command function is exposed to untrusted input by inspecting command logs for unusual arguments containing shell metacharacters like semicolons or backticks.

Impact Analysis

This vulnerability allows attackers to execute arbitrary commands on the server running mac-shell-mcp versions before 2.0.0. This could lead to unauthorized access, data theft, system compromise, or further network infiltration depending on the server's permissions and environment.

Compliance Impact

This vulnerability allows unauthorized command execution, which could lead to unauthorized data access, modification, or deletion. For GDPR, this could violate principles of data protection and user rights. For HIPAA, it may compromise protected health information integrity and confidentiality. Unauthorized access risks non-compliance with security and privacy requirements in both standards.

Mitigation Strategies

Upgrade to mac-shell-mcp version 2.0.0 or later immediately. If upgrading is not possible, disable the execute_command function or restrict access to trusted clients only. Review and harden command whitelists to block all dynamic argument parsing.

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