OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. From 5.0.0 to 6.10.1, OpenC3 COSMOS contains a critical remote code execution vulnerability reachable through the JSON-RPC API. When a JSON-RPC request uses the string form of certain APIs, attacker-controlled parameter text is parsed into values using String#convert_to_value. For array-like inputs, convert_to_value executes eval(). Because the cmd code path parses the command string before calling authorize(), an unauthenticated attacker can trigger Ruby code execution even though the request ultimately fails authorization (401). This vulnerability is fixed in 6.10.2.