PubSub in Apple Safari before 4.0.5 does not properly implement use of the Accept Cookies preference to block cookies, which makes it easier for remote web servers to track users by setting a cookie in a (1) RSS or (2) Atom feed.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A7051
https://exchange.xforce.ibmcloud.com/vulnerabilities/56830
http://www.securityfocus.com/bid/38675
http://www.securityfocus.com/bid/38671
http://support.apple.com/kb/HT4070
http://lists.apple.com/archives/security-announce/2010/Mar/msg00000.html