{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-55581", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-06-16T23:18:03.169Z", "datePublished": "2026-08-25T15:40:10.992Z", "dateUpdated": "2026-08-25T15:40:10.992Z"}, "containers": {"cna": {"title": "mcp-shell: Secure Mode Allowlist Bypass via Default `/bin/bash` Executable", "problemTypes": [{"descriptions": [{"cweId": "CWE-78", "lang": "en", "description": "CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-183", "lang": "en", "description": "CWE-183: Permissive List of Allowed Inputs", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-1188", "lang": "en", "description": "CWE-1188: Insecure Default Initialization of Resource", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 8.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}}], "references": [{"name": "https://github.com/sonirico/mcp-shell/security/advisories/GHSA-3x77-wg38-92r3", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/sonirico/mcp-shell/security/advisories/GHSA-3x77-wg38-92r3"}, {"name": "https://github.com/sonirico/mcp-shell/pull/16", "tags": ["x_refsource_MISC"], "url": "https://github.com/sonirico/mcp-shell/pull/16"}, {"name": "https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09f", "tags": ["x_refsource_MISC"], "url": "https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09f"}, {"name": "https://github.com/sonirico/mcp-shell/releases/tag/v0.6.0", "tags": ["x_refsource_MISC"], "url": "https://github.com/sonirico/mcp-shell/releases/tag/v0.6.0"}], "affected": [{"vendor": "sonirico", "product": "mcp-shell", "versions": [{"version": "< 0.6.0", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-08-25T15:40:10.992Z"}, "descriptions": [{"lang": "en", "value": "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."}], "source": {"advisory": "GHSA-3x77-wg38-92r3", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "mcp-shell", "vendor": "sonirico", "versions": [{"status": "affected", "version": "< 0.6.0"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-55581", "lastModified": "2026-08-25T16:16:55.470", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 8.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.5, "impactScore": 5.9, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-08-25T16:16:55.470", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09f"}, {"source": "security-advisories@github.com", "url": "https://github.com/sonirico/mcp-shell/pull/16"}, {"source": "security-advisories@github.com", "url": "https://github.com/sonirico/mcp-shell/releases/tag/v0.6.0"}, {"source": "security-advisories@github.com", "url": "https://github.com/sonirico/mcp-shell/security/advisories/GHSA-3x77-wg38-92r3"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-78"}, {"lang": "en", "value": "CWE-183"}, {"lang": "en", "value": "CWE-1188"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{}