CVE-2026-7730 in mcp-test-runner
Summary
by MITRE • 05/04/2026
A weakness has been identified in privsim mcp-test-runner 0.2.0. Impacted is the function child_process.spawn of the file src/index.ts of the component MCP Interface. Executing a manipulation of the argument command can lead to os command injection. The attack may be launched remotely. The exploit has been made available to the public and could be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.
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Analysis
by VulDB Data Team • 06/21/2026
The vulnerability identified in privsim mcp-test-runner version 0.2.0 represents a critical security flaw that enables remote os command injection through improper input validation in the child_process.spawn function. This weakness exists within the MCP Interface component of the application, specifically in the src/index.ts file where user-supplied command arguments are directly passed to the operating system without adequate sanitization or validation. The affected function serves as a bridge between the application's interface and the underlying operating system, creating a pathway for malicious actors to execute arbitrary commands on the host system. The vulnerability's remote exploitability means that attackers can trigger the injection through network-based interactions without requiring local access to the system, significantly expanding the attack surface and potential impact.
The technical implementation of this flaw stems from insufficient input validation and sanitization practices within the application's command execution pipeline. When the application processes user-provided command arguments through child_process.spawn, it fails to properly escape or filter special characters that could alter the intended command execution flow. This creates an environment where malicious input can be interpreted by the shell as additional commands, allowing attackers to execute arbitrary code with the privileges of the application process. The vulnerability aligns with CWE-78, which specifically addresses OS Command Injection flaws in software applications that improperly handle user input when constructing operating system commands. The attack vector is particularly dangerous because it leverages the Node.js child_process module, which is commonly used for system integration and process management, making it a frequent target for exploitation in web applications and system interfaces.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable complete system compromise when exploited by attackers. An attacker who successfully exploits this vulnerability could gain unauthorized access to the underlying system, potentially leading to data theft, system modification, or further lateral movement within a network. The fact that the exploit has been made publicly available significantly increases the risk level, as it removes the need for advanced technical skills to execute the attack. Organizations using this version of the mcp-test-runner are particularly vulnerable since the application appears to have been informed of the issue through a formal issue report but has failed to respond or implement a fix. This delay in remediation creates a window of opportunity for attackers to exploit the vulnerability before any patches or mitigations are deployed, potentially leading to widespread compromise across systems that rely on this testing framework.
The exploitation of this vulnerability can be mapped to several techniques described in the ATT&CK framework, particularly those related to command and control operations and privilege escalation. Attackers can leverage this flaw to establish persistent access, gather system information, or deploy additional malicious tools through the compromised system. The lack of response from the project maintainers compounds the security risk, as it suggests either limited resources for security maintenance or insufficient awareness of the vulnerability's severity. Organizations should immediately implement mitigations such as input validation, parameterized command execution, and network segmentation to reduce the risk of exploitation. Additionally, the project maintainers should be urged to prioritize the development of a security patch and provide clear communication about the vulnerability's status and remediation timeline to protect their user base from potential attacks.