The vulnerability resides in the Lobster extension of OpenClaw, where a Windows shell fallback is activated when a spawn failure occurs and the shell option is set to true. This path incorrectly handles tool‑provided arguments, allowing an attacker to inject arbitrary commands. The defect maps to CWE‑78 (OS Command Injection) and enables arbitrary command execution on the host system, compromising confidentiality, integrity, and availability of the affected machine.

Affected vendor is OpenClaw. Versions older than 2026.2.19, specifically any release from 2026.1.21 up to but not including 2026.2.19, are vulnerable. The issue manifests on Windows operating systems that run the OpenClaw platform and employ the Lobster extension.

The CVSS base score is 5.8, indicating moderate severity. The EPSS score is below 1%, suggesting the exploit is unlikely to be widespread or currently in use, and the vulnerability is not listed in the CISA KEV catalog. Exploitation requires an attacker to supply malicious workflow arguments to the Lobster extension; when the fallback to cmd.exe is triggered, the attacker can remotely or locally execute commands. Because the flaw is discovered within the application’s Windows shell handling, an attacker with sufficient input control can achieve full command execution, but no evidence of active exploitation exists yet.