CVE-2026-55581

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Source
https://cve.org/CVERecord?id=CVE-2026-55581
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-55581.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-55581
Aliases
Downstream
Related
Published
2026-08-25T15:40:10Z
Modified
2026-10-15T02:51:49Z
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 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.

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"
}
References

Affected packages

Git / github.com/sonirico/mcp-shell

Affected ranges

Type
GIT
Repo
https://github.com/sonirico/mcp-shell
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
df02c8c74044a950d5c085626da8de49c7551cd5
Fixed
f31377fce6ec31114e5a4398c0e5270552bce09f
Database specific
Show details 
{
    "extracted_events":  [
        {
            "range":  [
                {
                    "introduced":  "0"
                },
                {
                    "fixed":  "0.6.0"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StringRangeExpression"
        },
        {
            "range":  [
                {
                    "fixed":  "f31377fce6ec31114e5a4398c0e5270552bce09f"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "original_tag":  "v0.6.0",
            "range":  [
                {
                    "fixed":  "df02c8c74044a950d5c085626da8de49c7551cd5"
                }
            ],
            "source":  "REFERENCES_TAG"
        }
    ]
}

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/osv-test-cve-osv-conversion/osv-output/CVE-2026-55581.json"