What's going on with the CFO of Huawei being arrested; what is the US govt charging her with?

https://edition.cnn.com/2018/12/05/tech/huawei-cfo-arrested-canada/index.html?from=groupmessage

It seems it has something to do with Huawei devices supposedly enabling China to spy on people holding the devices, but what does this have to do with their CFO?

Or is the US govt just trying to get their hands on any of the Huawei execs?