Some vulnerabilities have been reported in Skype, which can be exploited by malicious people to cause a DoS or to compromise a user's system.

Affected Software:
Skype for Linux 0.x
Skype for Linux 1.x
Skype for Mac OS X 0.x
Skype for Mac OS X 1.x
Skype for Pocket PC 1.x
Skype for Windows 1.x

Solution:
Update to the fixed version.
http://www.skype.com/download/

http://secunia.com/advisories/17305/