Werkzeug is a comprehensive WSGI web application library. The debugger in affected versions of Werkzeug can allow an malicious user to execute code on a developer's machine under some circumstances. This requires the malicious user to get the developer to interact with a domain and subdomain they control, and enter the debugger PIN, but if they are successful it allows access to the debugger even if it is only running on localhost. This also requires the malicious user to guess a URL in the developer's application that will trigger the debugger. This vulnerability is fixed in 3.0.3.
Vulmon