---
id: CVE-2026-55581
title: >-
  mcp-shell is an MCP server for running shell commands securely, auditably, and
  on demand
summary: >-
  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
  ch…
severity: high
cvss: 8.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-78
  - CWE-183
  - CWE-1188
vendor: sonirico
product: github.com/sonirico/mcp-shell
affected:
  - github.com/sonirico/mcp-shell < 0.6.0
patched:
  - github.com/sonirico/mcp-shell 0.6.0
published: '2026-08-25'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:07:31.353'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55581'
references:
  - url: >-
      https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09f
    label: security-advisories@github.com
  - url: 'https://github.com/sonirico/mcp-shell/pull/16'
    label: security-advisories@github.com
  - url: 'https://github.com/sonirico/mcp-shell/releases/tag/v0.6.0'
    label: security-advisories@github.com
  - url: >-
      https://github.com/sonirico/mcp-shell/security/advisories/GHSA-3x77-wg38-92r3
    label: security-advisories@github.com
  - url: >-
      https://github.com/sonirico/mcp-shell/security/advisories/GHSA-3x77-wg38-92r3
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://github.com/advisories/GHSA-3x77-wg38-92r3'
  - url: 'https://github.com/sonirico/mcp-shell'
tags:
  - nvd
  - ghsa
  - go
  - osv
epss: 0.00454
epssPercentile: 0.36716
aliases:
  - GHSA-3x77-wg38-92r3
  - GO-2026-6290
ecosystem: go
ingestedAt: '2026-08-25T16:28:51.207Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-55581)

Affected packages:

- `github.com/sonirico/mcp-shell < 0.6.0`

Patched in:

- `github.com/sonirico/mcp-shell 0.6.0`

Source: https://github.com/advisories/GHSA-3x77-wg38-92r3