Safari 3 for Windows requires Windows XP or Windows Vista, a minimum of 256 MB of memory and a system with at least a 500 MHz Intel Pentium processor.

Safari had about 5 percent of the market share for Internet browsers with more than 18 million users when it was previously available only for Macintosh computers, according to Apple.

Though shortly after the release some securities problems were discovered and Apple issued an update. The weaknesses found could allow attackers to run malicious code and take control of target PCs.

David Maynor of Errata Security posted notice of a bug about two hours after Apple made Safari 3 available for Windows. He later discovered other six bugs. Four could be exploited to crash the browser and/or PC in a denial of service; the other two were remote execution vulnerabilities.

“Apple issued an update to the Safari for Windows public beta today to fix the security vulnerabilities that were reported earlier this week. Safari updates are delivered to beta testers through Apple’s Software Update Application,” an Apple spokesman told Macworld.