How secure is Cygwin in a multi-user environment?
As of version 1.5.13, the Cygwin developers are not aware of any feature in the cygwin dll that would allow users to gain privileges or to access objects to which they have no rights under Windows. However there is no guarantee that Cygwin is as secure as the Windows it runs on. Cygwin processes share some variables and are thus easier targets of denial of service type of attacks.