The SSL implementation in Apple Safari before 5.1.1 on Mac OS X before 10.7 accesses uninitialized memory during the processing of X.509 certificates, which allows remote web servers to execute arbitrary code via a crafted certificate.
https://exchange.xforce.ibmcloud.com/vulnerabilities/70568
http://support.apple.com/kb/HT5000
http://lists.apple.com/archives/Security-announce/2011//Oct/msg00004.html