Windows Safari users should apply this release promptly, as it addresses the following security vulnerabilities: 

Windows Safari 3.12 - Addresses recent security concerns
http://isc.sans.org/diary.html?storyid=4601

QUOTE: Safari 3.1.2 for Windows was released to address the following security vulnerabilities:

CVE-ID: CVE-2008-1573
Available for: Windows XP or Vista
Impact: Viewing a maliciously crafted BMP or GIF image may lead to information disclosure

CVE-ID: CVE-2008-2540
Available for: Windows XP or Vista
Impact: Saving untrusted files to the Windows desktop may lead to the execution of arbitrary code

CVE-ID: CVE-2008-2306
Available for: Windows XP or Vista
Impact: Visiting a malicious website which is in a trusted Internet Explorer zone may lead to the automatic execution of arbitrary code

Apple Safari for Windows - Release & Download Links
http://support.apple.com/kb/HT2092
http://www.apple.com/support/downloads/safari312forwindows.html

QUOTE: "This update is recommended for all Safari Windows users and includes stability improvements and the latest security updates".