{"cve":"CVE-2026-55580","nvd":{"published":"2026-08-25T16:16:55.317","modified":"2026-09-09T21:07:31.353","status":"Deferred","description":"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.","cvss_v4":{"vector":"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","score":8.6},"cvss_v3":null,"cwes":["CWE-78"],"references":["https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09f","https://github.com/sonirico/mcp-shell/pull/16","https://github.com/sonirico/mcp-shell/releases/tag/v0.6.0","https://github.com/sonirico/mcp-shell/security/advisories/GHSA-f5pj-2738-996m","https://github.com/sonirico/mcp-shell/security/advisories/GHSA-f5pj-2738-996m"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:50:17.453294893+00:00"},"epss":{"cve":"CVE-2026-55580","score":0.00197,"percentile":0.09425,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-f5pj-2738-996m","url":"https://osv.dev/vulnerability/GHSA-f5pj-2738-996m","summary":"mcp-shell — Security Disabled by Default in Bare-Binary Deploy Path + Shell Interpreter in Secure-Mode Allowlist","modified":"2026-08-26T15:25:57.720002566Z","packages":[{"ecosystem":"Go","name":"github.com/sonirico/mcp-shell","purl":"pkg:golang/github.com/sonirico/mcp-shell","ranges":["<0.6.0"],"fixed":["0.6.0"]}]},{"id":"GO-2026-6292","url":"https://osv.dev/vulnerability/GO-2026-6292","summary":"mcp-shell — Security Disabled by Default in Bare-Binary Deploy Path + Shell Interpreter in Secure-Mode Allowlist in github.com/sonirico/mcp-shell","modified":"2026-08-26T15:15:13.153924222Z","packages":[{"ecosystem":"Go","name":"github.com/sonirico/mcp-shell","purl":"pkg:golang/github.com/sonirico/mcp-shell","ranges":["<0.6.0"],"fixed":["0.6.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}