Emissary is a P2P based data-driven workflow engine. In versions 8.42.0 and below, Executrix.getCommand() is vulnerable to OS command injection because it interpolates temporary file paths into a /bin/sh -c shell command string without any escaping or input validation. The IN_FILE_ENDING and OUT_FILE_ENDING configuration keys flow directly into these paths, allowing a place author who can write or modify a .cfg file to inject arbitrary shell metacharacters that execute OS commands in the JVM process's security context. The framework already sanitizes placeName via an allowlist before embedding it in the same shell string, but applies no equivalent sanitization to file ending values. No runtime privileges beyond place configuration authorship, and no API or network access, are required to exploit this vulnerability. This is a framework-level defect with no safe mitigation available to downstream implementors, as Executrix provides neither escaping nor documented preconditions against metacharacters in file ending inputs. This issue has been fixed in version 8.43.0.