Wow. So what you are saying is that someone with knowledge of a company’s internal private package dependencies would be able to hijack their build process by publishing a higher-numbered version of the same package to the public PyPi? And even if the build system explicitly references the package version number, part of the time the package would be taken from the public PyPi instead of the company’s own package server?

How do you mitigate this, other than just totally blocking access to the public PyPi? Shouldn’t everyone be blocking access to PyPi, then, and only be relying on their own private package server?