This indicates an attack attempt to exploit a memory-corruption vulnerability in Apple Safari Webkit.
The vulnerability is caused by an error that occurs when the vulnerable software handles elements with run-in styling. A remote attacker may exploit this to execute arbitrary code via a crafted web page.
Safari 4 (Mac OS X 10.5)
Safari 4 (Mac OS X 10.4)
Safari 5 (Windows)
Safari 5 (Mac OS X 10.6)
Safari 5 (Mac OS X 10.5)
System Compromise: Remote attackers can gain control of vulnerable systems.
Refer to the vendor's web site for the suggested workaround: