Use-after-free vulnerability in WebKit in Apple Safari before 4.0.5 allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via HTML elements with right-to-left (RTL) text directionality. Per: http://lists.apple.com/archives/security-announce/2010/Mar/msg00000.
CVE-ID: CVE-2010-0049 Available for: Mac OS X v10.4.11, Mac OS X Server v10.4.11, Mac OS X v10.5.8, Mac OS X Server v10.5.8, Mac OS X v10.6.1 or later, Mac OS X Server v10.6.1 or later, Windows 7, Vista, XP Impact: Visiting a maliciously crafted website may lead to an unexpected application termination or arbitrary code execution Description: A use-after-free issue exists in the handling of HTML elements containing right-to-left displayed text. Visiting a maliciously crafted website may lead to an unexpected application termination or arbitrary code execution. This issue is addressed through improved memory reference tracking. Credit to wushi&Z of team509 for reporting this issue.