Secunia has updated its security advisory for the Safari vulnerability issued yesterday to its highest severity rating of “Extremely Critical,” from “Highly Critical.” The vulnerability could potentially allow malicious Web sites to compromise a vulnerable system through the Web browser. “It has been updated due to details about ease-of-exploitation, describing this to be very basic to exploit,” Secunia’s Jakob Balle told MacMinute. Apple today released a statement saying that it takes security “very seriously… and we are actively investigating this potential security issue.”