Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
react-dev-utils 0.4.0 through 11.0.3 exposes a function, getProcessForPort, where an input argument is concatenated into a command string to be executed. This function is typically used from react-scripts (in Create React App projects), where the usage is safe. Only when this function is manually invoked with user-provided values (ie: by custom code) is there the potential for command injection. If you're consuming it from react-scripts then this issue does not affect you.
CWE-78 - OS Command Injection
The OS command injection weakness (also known as shell injection) is a vulnerability which enables an attacker to run arbitrary OS commands on a server. This is done by modifying the intended downstream OS command and injecting arbitrary commands, enabling the execution of unauthorized OS commands. This has the potential to fully compromise the application along with all of its data, and, if the compromised process does not follow the principle of least privileges, it may compromise other parts of the hosting infrastructure as well. This weakness is listed as number ten in the 'CWE Top 25 Most Dangerous Software Weaknesses'.