On April 12th, 2016 a crucial security bug in Windows and Samba will be disclosed. We call it: Badlock. Engineers at Microsoft and the Samba Team are working together to get this problem fixed. Patches will be released on April 12th.
Admins and all of you responsible for Windows or Samba server infrastructure: Mark the date. (Again: It's April 12th, 2016.) Please get yourself ready to patch all systems on this day. We are pretty sure that there will be exploits soon after we publish all relevant information.