{"id":"CVE-2026-55581","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-55581","summary":"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,…","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.","published":"2026-08-25T16:16:55.470","modified":"2026-08-25T16:16:55.470","cvss":{"score":8.4,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09f","label":"sonirico/mcp-shell@f31377f"},"references":[{"type":"WEB","url":"https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09f"},{"type":"WEB","url":"https://github.com/sonirico/mcp-shell/pull/16"},{"type":"WEB","url":"https://github.com/sonirico/mcp-shell/releases/tag/v0.6.0"},{"type":"WEB","url":"https://github.com/sonirico/mcp-shell/security/advisories/GHSA-3x77-wg38-92r3"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-08-25T16:16:55.470"}}