CVE-2026-55581

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Source

https://cve.org/CVERecord?id=CVE-2026-55581

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55581.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-55581

Aliases

Published

2026-08-25T15:40:10.992Z

Modified

2026-08-27T11:47:33.999912165Z

Severity

8.4 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator

Summary

mcp-shell: Secure Mode Allowlist Bypass via Default `/bin/bash` Executable

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 allowedexecutables, while security.go validates only the first token and checkBlockedPatternsAndCommands does not reject the shell command-mode flag -c. A caller of the shellexec 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.

Database specific

{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55581.json",
    "cwe_ids": [
        "CWE-1188",
        "CWE-183",
        "CWE-78"
    ],
    "cna_assigner": "GitHub_M"
}

References

Affected packages

Git / github.com/sonirico/mcp-shell

Affected ranges

Type

GIT

Repo

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

Events

Introduced

Fixed

f31377fce6ec31114e5a4398c0e5270552bce09f

Fixed

df02c8c74044a950d5c085626da8de49c7551cd5

Database specific

Show details

{
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "0.6.0"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ]
}

Affected versions

v0.*

v0.1.0

v0.2.0

v0.2.2

v0.3.0

v0.3.1

v0.4.0

v0.5.0

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55581.json"