If you have a computer
the odds are really good that you have a clock that uses the NTP (network time protocol). While the problem is about the part of the server that is on the time server, the security flaw can be used to create all sorts of security havoc.
Here is a pointer to the article.
http://support.ntp.org/bin/view/Main/SecurityNotice
For those is Internet facing servers, make sure that you either upgrade as soon as possible or ensure that NTP is disabled. This may create some issues for those who only get their network time from a single source.
Use this Google string if you want to find out more: ntp security issues