This is a vulnerability about as serious as the heartbleed vulnerability. If you have not patched your servers, please do so. Servers that are internet-facing are particularly at risk, but linux installs and OSX machines are vulnerable as well.
http://www.troyhunt.com/2014/09/everything-you-need-to-know-about.html
I rest assured that the Postmonster General is aware of the issue.
We are well aware and taking appropriate measures.