CVE 2010-1418
Cross-site scripting (XSS) vulnerability in WebKit in Apple Safari before 5.0 on Mac OS X 10.5 through 10.6 and Windows, and before 4.1 on Mac OS X 10.4, allows remote attackers to inject arbitrary web script or HTML via a FRAME element with a SRC attribute composed of a javascript: sequence preceded by spaces.
See the 
CVE page on Mitre.org
for more details.
