Safari 3.2 contains a new version of the WebKit engine, which has been altered to limit the URL types that can be launched through the plug-in interface. WebKit has also been tweaked to run extra validation on JavaScript array indices, and perform better garbage collection. The majority of security updates in the browser are explicitly targeted at Windows XP and Vista users, however, such as remedies to JPEG and TIFF exploits, and other vulnerabilities in components like CoreGraphics and zlib. Aside from anti-phishing protection, the lone Mac security fix solves a problem in which disabling auto-completion would still leave data in Safari's page cache.