WebKit in Apple Safari before 5.0.3 on Mac OS X 10.5 through 10.6 and Windows, and before 4.1.3 on Mac OS X 10.4, does not properly handle the :first-letter pseudo-element in a Cascading Style Sheets (CSS) token sequence, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted web site.
CVSS Metrics
