Exposed Dangerous Method or Function

Summary

The webpack-dev-server allows users to use webpack with a development server that provides live reloading. The webpack-dev-server users' source code may be stolen when they access a malicious web site. Because the request for classic script by a script tag is not subject to same origin policy, an attacker can inject a malicious script in their site and run the script. Note that the attacker has to know the port and the output entrypoint script path. Combined with Prototype Pollution, the attacker can get a reference to the webpack runtime variables. By using `Function::toString` against the values in `__webpack_modules__`, the attacker can get the source code. This issue affects webpack-dev-server versions prior to 5.2.1.