sonirico mcp-shell up to 0.5.x Security Validator security.go SecurityValidator.validateCommand os command injection

Summaryinfo

A vulnerability was found in sonirico mcp-shell up to 0.5.x. It has been rated as critical. The affected element is the function SecurityValidator.validateCommand of the file security.go of the component Security Validator. Performing a manipulation results in os command injection. This vulnerability is known as CVE-2026-55580. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in sonirico mcp-shell up to 0.5.x. It has been classified as critical. This affects the function SecurityValidator.validateCommand of the file security.go of the component Security Validator. The manipulation with an unknown input leads to a os command injection vulnerability. CWE is classifying the issue as 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. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

mcp-shell is an MCP server for running shell commands securely, auditably, and on demand. Prior to 0.6.0, config.go initializes Security.Enabled to false, and when MCP_SHELL_SEC_CONFIG_FILE is unset, main.go starts the documented bare-binary deployment without a security policy. SecurityValidator.validateCommand in security.go then short-circuits and allows every command supplied to the shell_exec MCP tool, so an LLM connected over stdio can execute unrestricted OS commands as the mcp-shell process user. The README from-source installation and MCP client configuration omit MCP_SHELL_SEC_CONFIG_FILE, making the insecure state the documented default. This issue is fixed in version 0.6.0.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-55580 since 06/17/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1202 according to MITRE ATT&CK.

Upgrading to version 0.6.0 eliminates this vulnerability.

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Productinfo

Type

• Artificial Intelligence Software

Vendor

• sonirico

Name

• mcp-shell

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5

Website

• Product: https://github.com/sonirico/mcp-shell/

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