Last night (European time) a denial-of-service vulnerability in Apache 2.0.49 was found. To fix this problem we released an upgrade package for the Linux version of XAMPP.
This upgrade is only of interest for those people who a using XAMPP in a public environment. Like Internet.
People who only using XAMPP at home don't need to upgrade.
You can get the patch from the usual place (there you also find an explanation how to install the patch). More information about the vulnerability: here