Don't underplay it either though: with a compromised but unrevoked signing cert all it takes is a successful phish, or some problem to allow DNS poisoning (or hack a wireless AP, or …) to direct you to a fake site or (potentially worse as it might be less immediately noticeable and could quietly collect credentials/data for a while) send your automated tools to a malicious API.

It may not be directly exploitable on its own, which is the impression some reports give, but it is a serious hole to leave open especially with the current rate of old security issues being found, as it could be _incredibly_ useful to a malicious actor as part of an exploit chain.