A few days ago, Apple released Mac OS X Lion 10.7.4, with Security Update 2012-002. This new version incorporates fixes for more than 30 security vulnerabilities; the details, and CVE identifiers for the vulnerabilities fixed, are in the announcement bulletin.
Apple also released a new version of its Safari Web browser, 5.1.7, for both OS X and Windows. This version fixes four identified security flaws, which are itemized in the announcement. The new version will also disable outdated versions of the Adobe Flash Player plugin; it will offer the user an option to download an up-to-date version from Adobe’s site.
I recommend that you install these updates as soon as you conveniently can. You can obtain them via Software Update, or from the Apple download site.