, The Register 2005-05-09
Security researchers have discovered two unpatched vulnerabilities in Firefox, the popular alternative web browser. The security bugs affect even the latest version of Firefox (version 1.0.3) and create a means for attackers to seize control of vulnerable systems using cross-site scripting attacks.

Coldman
There are a lot of examples when MS based systems are secure (because their admins know exactly how to set them up - _correctly_), and there are a lot of Open Source (Linux/*bsd ...
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