CSS is a web design technology that almost every web site today is using. It controls things like colour, fonts, and most of the design on every web page.
A flaw has been discovered that can allow web site creators to know if you’ve been to a particular site. An example has been presented that lets web site owners know if you visit Digg, Del.icio.us, Reddit, and Facebook without having to ask.
This is more of a privacy concern rather than a security risk. The following tips will avoid it but it’s a little impractical to do:
- Turn off JavaScript (a lot of web sites today require JavaScript)
- Clear your browser history after you finish reading any pages you don’t want others to know about
It’s a documented bug in the CSS standard that might not get fixed for a while.