sonirico mcp-shell up to 0.5.x Shell Command Execution executor.go exec.CommandContext command os command injection

Summaryinfo

A vulnerability identified as critical has been detected in sonirico mcp-shell up to 0.5.x. This affects the function exec.CommandContext of the file executor.go of the component Shell Command Execution. The manipulation of the argument command leads to os command injection. This vulnerability is uniquely identified as CVE-2026-55581. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in sonirico mcp-shell up to 0.5.x. It has been rated as critical. This issue affects the function exec.CommandContext of the file executor.go of the component Shell Command Execution. The manipulation of the argument command with an unknown input leads to a os command injection vulnerability. Using CWE to declare the problem leads to 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. Impacted is 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, the default Docker security.yaml includes /bin/bash in allowed_executables, while security.go validates only the first token and checkBlockedPatternsAndCommands does not reject the shell command-mode flag -c. A caller of the shell_exec MCP tool can provide the command argument `/bin/bash -c <arbitrary-command>`, which passes validation and reaches executor.go, where parseCommand and exec.CommandContext execute the arbitrary command as mcpuser outside the intended allowlist. This issue is fixed in version 0.6.0.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-55581 since 06/17/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1202 for this issue.

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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