{"id":"CVE-2026-55580","summary":"mcp-shell — Security Disabled by Default in Bare-Binary Deploy Path + Shell Interpreter in Secure-Mode Allowlist","details":"mcp-shell is an MCP server for running shell commands securely, auditably, and on demand. Prior to 0.6.0, config.go initializes Security.Enabled to false, and when MCP_SHELL_SEC_CONFIG_FILE is unset, main.go starts the documented bare-binary deployment without a security policy. SecurityValidator.validateCommand in security.go then short-circuits and allows every command supplied to the shell_exec MCP tool, so an LLM connected over stdio can execute unrestricted OS commands as the mcp-shell process user. The README from-source installation and MCP client configuration omit MCP_SHELL_SEC_CONFIG_FILE, making the insecure state the documented default. This issue is fixed in version 0.6.0.","aliases":["GHSA-f5pj-2738-996m","GO-2026-6292"],"modified":"2026-08-27T11:47:33.999070661Z","published":"2026-08-25T15:42:36.474Z","database_specific":{"cwe_ids":["CWE-78"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55580.json","cna_assigner":"GitHub_M"},"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-2026-55580.json"},{"type":"ADVISORY","url":"https://github.com/sonirico/mcp-shell/security/advisories/GHSA-f5pj-2738-996m"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55580"},{"type":"FIX","url":"https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09f"},{"type":"FIX","url":"https://github.com/sonirico/mcp-shell/pull/16"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/sonirico/mcp-shell","events":[{"introduced":"0"},{"fixed":"f31377fce6ec31114e5a4398c0e5270552bce09f"},{"fixed":"df02c8c74044a950d5c085626da8de49c7551cd5"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"0.6.0"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v0.5.0","v0.4.0","v0.3.1","v0.3.0","v0.2.2","v0.2.0","v0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55580.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}]}