{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.6.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "f31377fce6ec31114e5a4398c0e5270552bce09f"
            },
            {
              "fixed": "df02c8c74044a950d5c085626da8de49c7551cd5"
            }
          ],
          "repo": "https://github.com/sonirico/mcp-shell",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-3x77-wg38-92r3"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-1188",
      "CWE-183",
      "CWE-78"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55581.json"
  },
  "details": "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 \u003carbitrary-command\u003e`, 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.",
  "id": "CVE-2026-55581",
  "modified": "2026-08-27T11:31:03.425296586Z",
  "published": "2026-08-25T15:40:10.992Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/sonirico/mcp-shell/releases/tag/v0.6.0"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55581.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/sonirico/mcp-shell/security/advisories/GHSA-3x77-wg38-92r3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55581"
    },
    {
      "type": "FIX",
      "url": "https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09f"
    },
    {
      "type": "FIX",
      "url": "https://github.com/sonirico/mcp-shell/pull/16"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "mcp-shell: Secure Mode Allowlist Bypass via Default `/bin/bash` Executable"
}