There's no reason to think that a tool that can find an 0-day in a repo cache can't work out how to make that host send a post request rather than a get request once it has its keys and is able to get it to make arbitrary web calls.

If the vulnerability is purely an open redirect that doesn't work for me.

Clearly there was a hole in the software but I don't think open redirect is the likely initial problem.

Hopefully we will find out for sure in a few days.