{"apiVersion":"1.0","identifier":"CVE-2026-55581","description":"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.","publishedAt":"2026-08-25T16:16:55","lastModifiedAt":"2026-08-25T19:16:50","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55581","cvssScore":8.4,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","epssProbability":0.0034,"riskScore":0.87,"affectedProduct":"mcp-shell","affectedVersions":"<0.6.0","vulnerabilityType":"Library","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-55581","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-55581","en":"https://www.redsauce.net/en/cves/CVE-2026-55581","fr":"https://www.redsauce.net/fr/cves/CVE-2026-55581","pt":"https://www.redsauce.net/pt/cves/CVE-2026-55581","de":"https://www.redsauce.net/de/cves/CVE-2026-55581","sk":"https://www.redsauce.net/sk/cves/CVE-2026-55581","el":"https://www.redsauce.net/el/cves/CVE-2026-55581"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-55581"}}